refactor: add general keybinds, fix buggy movement

Adds back some of the general program keybinds, and fixes both a bug causing
widget movement via keybinds to be incorrect, and not correcting the
last selected widget in the layout tree rows/cols after clicking/setting
the default widget!

17 files changed, 490 insertions, 267 deletions

diff --git a/docs/content/usage/general-usage.md b/docs/content/usage/general-usage.md
index 4bfcdb61..eb457aef 100644
--- a/docs/content/usage/general-usage.md
+++ b/docs/content/usage/general-usage.md
@@ -41,8 +41,8 @@ Note that key bindings are generally case-sensitive.
 | ------------------------------------------------------------ | ------------------------------------------------------------ |
 | ++q++ , ++ctrl+c++                                           | Quit                                                         |
 | ++esc++                                                      | Close dialog windows, search, widgets, or exit expanded mode |
-| ++ctrl+r++                                                   | Reset display and any collected data                         |
-| ++f++                                                        | Freeze/unfreeze updating with new data                       |
+| ++ctrl+r++                                                   | Resets any collected data                                    |
+| ++f++                                                        | Toggles freezing, which stops new data from being shown     |
 | ++question++                                                 | Open help menu                                               |
 | ++e++                                                        | Toggle expanding the currently selected widget               |
 | ++ctrl+up++ <br/> ++shift+up++ <br/> ++K++ <br/> ++W++       | Select the widget above                                      |
diff --git a/src/app.rs b/src/app.rs
index 7e2451b6..b3409d3f 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -104,19 +104,29 @@ pub struct AppConfigFields {
     pub no_write: bool,
     pub show_table_scroll_position: bool,
     pub is_advanced_kill: bool,
-    // TODO: Remove these, move network details state-side.
     pub network_unit_type: DataUnit,
     pub network_scale_type: AxisScaling,
     pub network_use_binary_prefix: bool,
 }
 
+/// The [`FrozenState`] indicates whether the application state should be frozen; if it is, save a snapshot of
+/// the data collected at that instant.
+pub enum FrozenState {
+    NotFrozen,
+    Frozen(DataCollection),
+}
+
+impl Default for FrozenState {
+    fn default() -> Self {
+        Self::NotFrozen
+    }
+}
+
 pub struct AppState {
     pub dd_err: Option<String>,
 
     to_delete_process_list: Option<(String, Vec<Pid>)>,
 
-    pub is_frozen: bool,
-
     pub canvas_data: canvas::DisplayableData,
 
     pub data_collection: DataCollection,
@@ -161,6 +171,7 @@ pub struct AppState {
     pub widget_lookup_map: FxHashMap<NodeId, TmpBottomWidget>,
     pub layout_tree: Arena<LayoutNode>,
     pub layout_tree_root: NodeId,
+    frozen_state: FrozenState,
 }
 
 impl AppState {
@@ -189,7 +200,6 @@ impl AppState {
             // Use defaults.
             dd_err: Default::default(),
             to_delete_process_list: Default::default(),
-            is_frozen: Default::default(),
             canvas_data: Default::default(),
             data_collection: Default::default(),
             is_expanded: Default::default(),
@@ -211,37 +221,30 @@ impl AppState {
             basic_mode_use_percent: Default::default(),
             is_force_redraw: Default::default(),
             is_determining_widget_boundary: Default::default(),
+            frozen_state: Default::default(),
         }
     }
 
-    pub fn reset(&mut self) {
-        // Reset multi
-        self.reset_multi_tap_keys();
+    pub fn is_frozen(&self) -> bool {
+        matches!(self.frozen_state, FrozenState::Frozen(_))
+    }
 
-        // Reset dialog state
-        self.help_dialog_state.is_showing_help = false;
-        self.delete_dialog_state.is_showing_dd = false;
+    pub fn toggle_freeze(&mut self) {
+        if matches!(self.frozen_state, FrozenState::Frozen(_)) {
+            self.frozen_state = FrozenState::NotFrozen;
+        } else {
+            self.frozen_state = FrozenState::Frozen(self.data_collection.clone());
+        }
+    }
 
-        // Close all searches and reset it
-        self.proc_state
-            .widget_states
+    pub fn reset(&mut self) {
+        // Call reset on all widgets.
+        self.widget_lookup_map
             .values_mut()
-            .for_each(|state| {
-                state.process_search_state.search_state.reset();
-            });
-        self.proc_state.force_update_all = true;
-
-        // Clear current delete list
-        self.to_delete_process_list = None;
-        self.dd_err = None;
+            .for_each(|widget| widget.reset());
 
         // Unfreeze.
-        self.is_frozen = false;
-
-        // Reset zoom
-        self.reset_cpu_zoom();
-        self.reset_mem_zoom();
-        self.reset_net_zoom();
+        self.frozen_state = FrozenState::NotFrozen;
 
         // Reset data
         self.data_collection.reset();
@@ -259,10 +262,77 @@ impl AppState {
         self.dd_err = None;
     }
 
+    /// Handles a global event involving a char.
+    fn handle_global_char(&mut self, c: char) -> EventResult {
+        if c.is_ascii_control() {
+            EventResult::NoRedraw
+        } else {
+            // Check for case-sensitive bindings first.
+            match c {
+                'H' | 'A' => self.move_to_widget(MovementDirection::Left),
+                'L' | 'D' => self.move_to_widget(MovementDirection::Right),
+                'K' | 'W' => self.move_to_widget(MovementDirection::Up),
+                'J' | 'S' => self.move_to_widget(MovementDirection::Down),
+                _ => {
+                    let c = c.to_ascii_lowercase();
+                    match c {
+                        'q' => EventResult::Quit,
+                        'e' => {
+                            if self.app_config_fields.use_basic_mode {
+                                EventResult::NoRedraw
+                            } else {
+                                self.is_expanded = !self.is_expanded;
+                                EventResult::Redraw
+                            }
+                        }
+                        '?' => {
+                            self.help_dialog_state.is_showing_help = true;
+                            EventResult::Redraw
+                        }
+                        'f' => {
+                            self.toggle_freeze();
+                            if !self.is_frozen() {
+                                let data_collection = &self.data_collection;
+                                self.widget_lookup_map
+                                    .iter_mut()
+                                    .for_each(|(_id, widget)| widget.update_data(data_collection));
+                            }
+                            EventResult::Redraw
+                        }
+                        _ => EventResult::NoRedraw,
+                    }
+                }
+            }
+        }
+    }
+
+    /// Moves to a widget.
+    fn move_to_widget(&mut self, direction: MovementDirection) -> EventResult {
+        let layout_tree = &mut self.layout_tree;
+        let previous_selected = self.selected_widget;
+        if let Some(widget) = self.widget_lookup_map.get_mut(&self.selected_widget) {
+            match move_widget_selection(layout_tree, widget, self.selected_widget, direction) {
+                MoveWidgetResult::ForceRedraw(new_widget_id) => {
+                    self.selected_widget = new_widget_id;
+                    EventResult::Redraw
+                }
+                MoveWidgetResult::NodeId(new_widget_id) => {
+                    self.selected_widget = new_widget_id;
+
+                    if previous_selected != self.selected_widget {
+                        EventResult::Redraw
+                    } else {
+                        EventResult::NoRedraw
+                    }
+                }
+            }
+        } else {
+            EventResult::NoRedraw
+        }
+    }
+
     /// Handles a global [`KeyEvent`], and returns an [`EventResult`].
     fn handle_global_shortcut(&mut self, event: KeyEvent) -> EventResult {
-        // TODO: Write this.
-
         if event.modifiers.is_empty() {
             match event.code {
                 KeyCode::Esc => {
@@ -280,24 +350,33 @@ impl AppState {
                         EventResult::NoRedraw
                     }
                 }
-                KeyCode::Char('q') => EventResult::Quit,
-                KeyCode::Char('e') => {
-                    if self.app_config_fields.use_basic_mode {
-                        EventResult::NoRedraw
-                    } else {
-                        self.is_expanded = !self.is_expanded;
-                        EventResult::Redraw
-                    }
-                }
-                KeyCode::Char('?') => {
-                    self.help_dialog_state.is_showing_help = true;
+                KeyCode::Char(c) => self.handle_global_char(c),
+                _ => EventResult::NoRedraw,
+            }
+        } else if let KeyModifiers::CONTROL = event.modifiers {
+            match event.code {
+                KeyCode::Char('c') | KeyCode::Char('C') => EventResult::Quit,
+                KeyCode::Char('r') | KeyCode::Char('R') => {
+                    self.reset();
+                    let data_collection = &self.data_collection;
+                    self.widget_lookup_map
+                        .iter_mut()
+                        .for_each(|(_id, widget)| widget.update_data(data_collection));
                     EventResult::Redraw
                 }
+                KeyCode::Left => self.move_to_widget(MovementDirection::Left),
+                KeyCode::Right => self.move_to_widget(MovementDirection::Right),
+                KeyCode::Up => self.move_to_widget(MovementDirection::Up),
+                KeyCode::Down => self.move_to_widget(MovementDirection::Down),
                 _ => EventResult::NoRedraw,
             }
-        } else if let KeyModifiers::CONTROL = event.modifiers {
+        } else if let KeyModifiers::SHIFT = event.modifiers {
             match event.code {
-                KeyCode::Char('c') => EventResult::Quit,
+                KeyCode::Left => self.move_to_widget(MovementDirection::Left),
+                KeyCode::Right => self.move_to_widget(MovementDirection::Right),
+                KeyCode::Up => self.move_to_widget(MovementDirection::Up),
+                KeyCode::Down => self.move_to_widget(MovementDirection::Down),
+                KeyCode::Char(c) => self.handle_global_char(c),
                 _ => EventResult::NoRedraw,
             }
         } else {
@@ -317,7 +396,14 @@ impl AppState {
                 }
                 ReturnSignal::Update => {
                     if let Some(widget) = self.widget_lookup_map.get_mut(&self.selected_widget) {
-                        widget.update_data(&self.data_collection);
+                        match &self.frozen_state {
+                            FrozenState::NotFrozen => {
+                                widget.update_data(&self.data_collection);
+                            }
+                            FrozenState::Frozen(frozen_data) => {
+                                widget.update_data(frozen_data);
+                            }
+                        }
                     }
                     EventResult::Redraw
                 }
@@ -379,7 +465,11 @@ impl AppState {
                                     if was_id_already_selected {
                                         return self.convert_widget_event_result(result);
                                     } else {
-                                        // If the weren't equal, *force* a redraw.
+                                        // If the weren't equal, *force* a redraw, and correct the layout tree.
+                                        correct_layout_last_selections(
+                                            &mut self.layout_tree,
+                                            self.selected_widget,
+                                        );
                                         let _ = self.convert_widget_event_result(result);
                                         return EventResult::Redraw;
                                     }
@@ -402,7 +492,7 @@ impl AppState {
             BottomEvent::Update(new_data) => {
                 self.data_collection.eat_data(new_data);
 
-                if !self.is_frozen {
+                if !self.is_frozen() {
                     let data_collection = &self.data_collection;
                     self.widget_lookup_map
                         .iter_mut()
@@ -1599,12 +1689,7 @@ impl AppState {
             'G' => self.skip_to_last(),
             'k' => self.on_up_key(),
             'j' => self.on_down_key(),
-            'f' => {
-                self.is_frozen = !self.is_frozen;
-                if self.is_frozen {
-                    self.data_collection.set_frozen_time();
-                }
-            }
+            'f' => {}
             'C' => {
                 // self.open_config(),
             }
diff --git a/src/app/data_farmer.rs b/src/app/data_farmer.rs
index 25d265ab..c2747289 100644
--- a/src/app/data_farmer.rs
+++ b/src/app/data_farmer.rs
@@ -26,7 +26,7 @@ use regex::Regex;
 pub type TimeOffset = f64;
 pub type Value = f64;
 
-#[derive(Debug, Default)]
+#[derive(Clone, Debug, Default)]
 pub struct TimedData {
     pub rx_data: Value,
     pub tx_data: Value,
@@ -41,14 +41,14 @@ pub struct TimedData {
 /// collected, and what is needed to convert into a displayable form.
 ///
 /// If the app is *frozen* - that is, we do not want to *display* any changing
-/// data, keep updating this, don't convert to canvas displayable data!
+/// data, keep updating this. As of 2021-09-08, we just clone the current collection
+/// when it freezes to have a snapshot floating around.
 ///
 /// Note that with this method, the *app* thread is responsible for cleaning -
 /// not the data collector.
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct DataCollection {
     pub current_instant: Instant,
-    pub frozen_instant: Option<Instant>,
     pub timed_data_vec: Vec<(Instant, TimedData)>,
     pub network_harvest: network::NetworkHarvest,
     pub memory_harvest: memory::MemHarvest,
@@ -70,7 +70,6 @@ impl Default for DataCollection {
     fn default() -> Self {
         DataCollection {
             current_instant: Instant::now(),
-            frozen_instant: None,
             timed_data_vec: Vec::default(),
             network_harvest: network::NetworkHarvest::default(),
             memory_harvest: memory::MemHarvest::default(),
@@ -92,21 +91,19 @@ impl Default for DataCollection {
 
 impl DataCollection {
     pub fn reset(&mut self) {
-        self.timed_data_vec = Vec::default();
-        self.network_harvest = network::NetworkHarvest::default();
-        self.memory_harvest = memory::MemHarvest::default();
-        self.swap_harvest = memory::MemHarvest::default();
-        self.cpu_harvest = cpu::CpuHarvest::default();
-        self.process_harvest = Vec::default();
-        self.disk_harvest = Vec::default();
-        self.io_harvest = disks::IoHarvest::default();
-        self.io_labels_and_prev = Vec::default();
-        self.temp_harvest = Vec::default();
-        self.battery_harvest = Vec::default();
-    }
-
-    pub fn set_frozen_time(&mut self) {
-        self.frozen_instant = Some(self.current_instant);
+        self.timed_data_vec = Default::default();
+        self.network_harvest = Default::default();
+        self.memory_harvest = Default::default();
+        self.swap_harvest = Default::default();
+        self.cpu_harvest = Default::default();
+        self.process_harvest = Default::default();
+        self.process_name_pid_map = Default::default();
+        self.process_cmd_pid_map = Default::default();
+        self.disk_harvest = Default::default();
+        self.io_harvest = Default::default();
+        self.io_labels_and_prev = Default::default();
+        self.temp_harvest = Default::default();
+        self.battery_harvest = Default::default();
     }
 
     pub fn clean_data(&mut self, max_time_millis: u64) {
diff --git a/src/app/event.rs b/src/app/event.rs
index a6afb2d8..9201e2c0 100644
--- a/src/app/event.rs
+++ b/src/app/event.rs
@@ -45,7 +45,7 @@ pub enum WidgetEventResult {
 
 /// How a widget should handle a widget selection request.
 pub enum SelectionAction {
-    /// This event occurs if the widget internally handled the selection action.
+    /// This event occurs if the widget internally handled the selection action. A redraw is required.
     Handled,
     /// This event occurs if the widget did not handle the selection action; the caller must handle it.
     NotHandled,
diff --git a/src/app/layout_manager.rs b/src/app/layout_manager.rs
index 9b88fb8a..61d17924 100644
--- a/src/app/layout_manager.rs
+++ b/src/app/layout_manager.rs
@@ -997,9 +997,9 @@ Supported widget names:
 // --- New stuff ---
 
 /// Represents a row in the layout tree.
-#[derive(PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub struct RowLayout {
-    last_selected_index: usize,
+    last_selected: Option<NodeId>,
     pub parent_rule: LayoutRule,
     pub bound: Rect,
 }
@@ -1007,7 +1007,7 @@ pub struct RowLayout {
 impl RowLayout {
     fn new(parent_rule: LayoutRule) -> Self {
         Self {
-            last_selected_index: 0,
+            last_selected: None,
             parent_rule,
             bound: Rect::default(),
         }
@@ -1015,9 +1015,9 @@ impl RowLayout {
 }
 
 /// Represents a column in the layout tree.
-#[derive(PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub struct ColLayout {
-    last_selected_index: usize,
+    last_selected: Option<NodeId>,
     pub parent_rule: LayoutRule,
     pub bound: Rect,
 }
@@ -1025,7 +1025,7 @@ pub struct ColLayout {
 impl ColLayout {
     fn new(parent_rule: LayoutRule) -> Self {
         Self {
-            last_selected_index: 0,
+            last_selected: None,
             parent_rule,
             bound: Rect::default(),
         }
@@ -1033,7 +1033,7 @@ impl ColLayout {
 }
 
 /// Represents a widget in the layout tree.
-#[derive(PartialEq, Eq, Clone, Default)]
+#[derive(Debug, PartialEq, Eq, Clone, Default)]
 pub struct WidgetLayout {
     pub bound: Rect,
 }
@@ -1042,7 +1042,7 @@ pub struct WidgetLayout {
 /// - [`LayoutNode::Row`] (a non-leaf that distributes its children horizontally)
 /// - [`LayoutNode::Col`] (a non-leaf node that distributes its children vertically)
 /// - [`LayoutNode::Widget`] (a leaf node that contains the ID of the widget it is associated with)
-#[derive(PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub enum LayoutNode {
     /// A non-leaf that distributes its children horizontally
     Row(RowLayout),
@@ -1382,6 +1382,8 @@ pub fn create_layout_tree(
         ));
     }
 
+    correct_layout_last_selections(&mut arena, selected);
+
     Ok(LayoutCreationOutput {
         layout_tree: arena,
         root: root_id,
@@ -1391,6 +1393,35 @@ pub fn create_layout_tree(
     })
 }
 
+/// We may have situations where we  also have to make sure the correct layout indices are selected.
+/// For example, when we select a widget by clicking, we want to update the layout so that it's as if a user
+/// manually moved to it via keybinds.
+///
+/// We can do this by just going through the ancestors, starting from the widget itself.
+pub fn correct_layout_last_selections(arena: &mut Arena<LayoutNode>, selected: NodeId) {
+    let mut selected_ancestors = selected.ancestors(&arena).collect::<Vec<_>>();
+    let prev_node = selected_ancestors.pop();
+    if let Some(mut prev_node) = prev_node {
+        for node in selected_ancestors {
+            if let Some(layout_node) = arena.get_mut(node).map(|n| n.get_mut()) {
+                match layout_node {
+                    LayoutNode::Row(RowLayout { last_selected, .. })
+                    | LayoutNode::Col(ColLayout { last_selected, .. }) => {
+                        *last_selected = Some(prev_node);
+                    }
+                    LayoutNode::Widget(_) => {}
+                }
+            }
+            prev_node = node;
+        }
+    }
+}
+
+pub enum MoveWidgetResult {
+    ForceRedraw(NodeId),
+    NodeId(NodeId),
+}
+
 /// Attempts to find and return the selected [`BottomWidgetId`] after moving in a direction.
 ///
 /// Note this function assumes a properly built tree - if not, bad things may happen! We generally assume that:
@@ -1399,7 +1430,7 @@ pub fn create_layout_tree(
 pub fn move_widget_selection(
     layout_tree: &mut Arena<LayoutNode>, current_widget: &mut TmpBottomWidget,
     current_widget_id: NodeId, direction: MovementDirection,
-) -> NodeId {
+) -> MoveWidgetResult {
     // We first give our currently-selected widget a chance to react to the movement - it may handle it internally!
     let handled = match direction {
         MovementDirection::Left => current_widget.handle_widget_selection_left(),
@@ -1408,16 +1439,18 @@ pub fn move_widget_selection(
         MovementDirection::Down => current_widget.handle_widget_selection_down(),
     };
 
+    // TODO: Do testing.
+
     match handled {
         SelectionAction::Handled => {
             // If it was handled by the widget, then we don't have to do anything - return the current one.
-            current_widget_id
+            MoveWidgetResult::ForceRedraw(current_widget_id)
         }
         SelectionAction::NotHandled => {
             /// Keeps traversing up the `layout_tree` until it hits a parent where `current_id` is a child and parent
             /// is a [`LayoutNode::Row`], returning its parent's [`NodeId`] and the child's [`NodeId`] (in that order).
             /// If this crawl fails (i.e. hits a root, it is an invalid tree for some reason), it returns [`None`].
-            fn find_first_row(
+            fn find_parent_row(
                 layout_tree: &Arena<LayoutNode>, current_id: NodeId,
             ) -> Option<(NodeId, NodeId)> {
                 layout_tree
@@ -1430,7 +1463,7 @@ pub fn move_widget_selection(
                     })
                     .and_then(|(parent_id, parent_node)| match parent_node.get() {
                         LayoutNode::Row(_) => Some((parent_id, current_id)),
-                        LayoutNode::Col(_) => find_first_row(layout_tree, parent_id),
+                        LayoutNode::Col(_) => find_parent_row(layout_tree, parent_id),
                         LayoutNode::Widget(_) => None,
                     })
             }
@@ -1438,7 +1471,7 @@ pub fn move_widget_selection(
             /// Keeps traversing up the `layout_tree` until it hits a parent where `current_id` is a child and parent
             /// is a [`LayoutNode::Col`], returning its parent's [`NodeId`] and the child's [`NodeId`] (in that order).
             /// If this crawl fails (i.e. hits a root, it is an invalid tree for some reason), it returns [`None`].
-            fn find_first_col(
+            fn find_parent_col(
                 layout_tree: &Arena<LayoutNode>, current_id: NodeId,
             ) -> Option<(NodeId, NodeId)> {
                 layout_tree
@@ -1450,7 +1483,7 @@ pub fn move_widget_selection(
                             .map(|parent_node| (parent_id, parent_node))
                     })
                     .and_then(|(parent_id, parent_node)| match parent_node.get() {
-                        LayoutNode::Row(_) => find_first_col(layout_tree, parent_id),
+                        LayoutNode::Row(_) => find_parent_col(layout_tree, parent_id),
                         LayoutNode::Col(_) => Some((parent_id, current_id)),
                         LayoutNode::Widget(_) => None,
                     })
@@ -1461,21 +1494,19 @@ pub fn move_widget_selection(
                 if let Some(current_node) = layout_tree.get(current_id) {
                     match current_node.get() {
                         LayoutNode::Row(RowLayout {
-                            last_selected_index,
+                            last_selected,
                             parent_rule: _,
                             bound: _,
                         })
                         | LayoutNode::Col(ColLayout {
-                            last_selected_index,
+                            last_selected,
                             parent_rule: _,
                             bound: _,
                         }) => {
-                            if let Some(next_child) =
-                                current_id.children(layout_tree).nth(*last_selected_index)
-                            {
+                            if let Some(next_child) = *last_selected {
                                 descend_to_leaf(layout_tree, next_child)
                             } else {
-                                current_id
+                                current_node.first_child().unwrap_or(current_id)
                             }
                         }
                         LayoutNode::Widget(_) => {
@@ -1493,7 +1524,7 @@ pub fn move_widget_selection(
             // on the tree layout to help us decide where to go.
             // Movement logic is inspired by i3. When we enter a new column/row, we go to the *last* selected
             // element; if we can't, go to the nearest one.
-            match direction {
+            let proposed_id = match direction {
                 MovementDirection::Left => {
                     // When we move "left":
                     // 1. Look for the parent of the current widget.
@@ -1513,7 +1544,8 @@ pub fn move_widget_selection(
                     fn find_left(
                         layout_tree: &mut Arena<LayoutNode>, current_id: NodeId,
                     ) -> NodeId {
-                        if let Some((parent_id, child_id)) = find_first_row(layout_tree, current_id)
+                        if let Some((parent_id, child_id)) =
+                            find_parent_row(layout_tree, current_id)
                         {
                             if let Some(prev_sibling) =
                                 child_id.preceding_siblings(layout_tree).nth(1)
@@ -1521,16 +1553,17 @@ pub fn move_widget_selection(
                                 // Subtract one from the currently selected index...
                                 if let Some(parent) = layout_tree.get_mut(parent_id) {
                                     if let LayoutNode::Row(row) = parent.get_mut() {
-                                        row.last_selected_index =
-                                            row.last_selected_index.saturating_sub(1);
+                                        row.last_selected = Some(prev_sibling);
                                     }
                                 }
 
                                 // Now descend downwards!
                                 descend_to_leaf(layout_tree, prev_sibling)
-                            } else {
+                            } else if parent_id != current_id {
                                 // Darn, we can't go further back! Recurse on this ID.
-                                find_left(layout_tree, child_id)
+                                find_left(layout_tree, parent_id)
+                            } else {
+                                current_id
                             }
                         } else {
                             // Failed, just return the current ID.
@@ -1546,23 +1579,26 @@ pub fn move_widget_selection(
                     fn find_right(
                         layout_tree: &mut Arena<LayoutNode>, current_id: NodeId,
                     ) -> NodeId {
-                        if let Some((parent_id, child_id)) = find_first_row(layout_tree, current_id)
+                        if let Some((parent_id, child_id)) =
+                            find_parent_row(layout_tree, current_id)
                         {
-                            if let Some(prev_sibling) =
+                            if let Some(following_sibling) =
                                 child_id.following_siblings(layout_tree).nth(1)
                             {
                                 // Add one to the currently selected index...
                                 if let Some(parent) = layout_tree.get_mut(parent_id) {
                                     if let LayoutNode::Row(row) = parent.get_mut() {
-                                        row.last_selected_index += 1;
+                                        row.last_selected = Some(following_sibling);
                                     }
                                 }
 
                                 // Now descend downwards!
-                                descend_to_leaf(layout_tree, prev_sibling)
-                            } else {
+                                descend_to_leaf(layout_tree, following_sibling)
+                            } else if parent_id != current_id {
                                 // Darn, we can't go further back! Recurse on this ID.
-                                find_right(layout_tree, child_id)
+                                find_right(layout_tree, parent_id)
+                            } else {
+                                current_id
                             }
                         } else {
                             // Failed, just return the current ID.
@@ -1578,7 +1614,8 @@ pub fn move_widget_selection(
                     fn find_above(
                         layout_tree: &mut Arena<LayoutNode>, current_id: NodeId,
                     ) -> NodeId {
-                        if let Some((parent_id, child_id)) = find_first_col(layout_tree, current_id)
+                        if let Some((parent_id, child_id)) =
+                            find_parent_col(layout_tree, current_id)
                         {
                             if let Some(prev_sibling) =
                                 child_id.preceding_siblings(layout_tree).nth(1)
@@ -1586,16 +1623,17 @@ pub fn move_widget_selection(
                                 // Subtract one from the currently selected index...
                                 if let Some(parent) = layout_tree.get_mut(parent_id) {
                                     if let LayoutNode::Col(row) = parent.get_mut() {
-                                        row.last_selected_index =
-                                            row.last_selected_index.saturating_sub(1);
+                                        row.last_selected = Some(prev_sibling);
                                     }
                                 }
 
                                 // Now descend downwards!
                                 descend_to_leaf(layout_tree, prev_sibling)
-                            } else {
+                            } else if parent_id != current_id {
                                 // Darn, we can't go further back! Recurse on this ID.
-                                find_above(layout_tree, child_id)
+                                find_above(layout_tree, parent_id)
+                            } else {
+                                current_id
                             }
                         } else {
                             // Failed, just return the current ID.
@@ -1611,23 +1649,26 @@ pub fn move_widget_selection(
                     fn find_below(
                         layout_tree: &mut Arena<LayoutNode>, current_id: NodeId,
                     ) -> NodeId {
-                        if let Some((parent_id, child_id)) = find_first_col(layout_tree, current_id)
+                        if let Some((parent_id, child_id)) =
+                            find_parent_col(layout_tree, current_id)
                         {
-                            if let Some(prev_sibling) =
+                            if let Some(following_sibling) =
                                 child_id.following_siblings(layout_tree).nth(1)
                             {
                                 // Add one to the currently selected index...
                                 if let Some(parent) = layout_tree.get_mut(parent_id) {
                                     if let LayoutNode::Col(row) = parent.get_mut() {
-                                        row.last_selected_index += 1;
+                                        row.last_selected = Some(following_sibling);
                                     }
                                 }
 
                                 // Now descend downwards!
-                                descend_to_leaf(layout_tree, prev_sibling)
-                            } else {
+                                descend_to_leaf(layout_tree, following_sibling)
+                            } else if parent_id != current_id {
                                 // Darn, we can't go further back! Recurse on this ID.
-                                find_below(layout_tree, child_id)
+                                find_below(layout_tree, parent_id)
+                            } else {
+                                current_id
                             }
                         } else {
                             // Failed, just return the current ID.
@@ -1636,6 +1677,12 @@ pub fn move_widget_selection(
                     }
                     find_below(layout_tree, current_widget_id)
                 }
+            };
+
+            if let Some(LayoutNode::Widget(_)) = layout_tree.get(proposed_id).map(|n| n.get()) {
+                MoveWidgetResult::NodeId(proposed_id)
+            } else {
+                MoveWidgetResult::NodeId(current_widget_id)
             }
         }
     }
diff --git a/src/app/widgets.rs b/src/app/widgets.rs
index cac6a032..ffc08cd6 100644
--- a/src/app/wi