Add indicator for recent icon IDs in prefs dialog

extension.js

@@ -52,6 +52,8 @@ export default class DashToDockExtension extends Extension.Extension {
     enable() {
         this._isEnabled = true;
         SettingsManager.initialize(this);
+        const settings = SettingsManager.getDefault().gsettings;
+        settings.reset('recent-icons'); // clear in preparation of new collection
         Util.tryCleanupOldIndicators();
         this._maybeEnableAfterNameAvailable();
         TrayIconsManager.TrayIconsManager.initialize();

indicatorStatusIcon.js

@@ -15,6 +15,7 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 import Clutter from 'gi://Clutter';
+import GLib from 'gi://GLib';
 import Gio from 'gi://Gio';
 import GObject from 'gi://GObject';
 import St from 'gi://St';
@@ -323,13 +324,24 @@ class IndicatorStatusIcon extends BaseStatusIcon {
         }
     }
 
+    _addToRecentIcons() {
+        const settings = SettingsManager.getDefaultGSettings();
+        const iconIDs = settings.get_value('recent-icons').deep_unpack();
+
+        if (this._indicator.id && !iconIDs.includes(this._indicator.id)) {
+            iconIDs.push(this._indicator.id);
+            settings.set_value('recent-icons', new GLib.Variant('as', iconIDs));
+        }
+    }
+
     _showIfReady() {
         if (!this.isReady())
             return;
 
         this._updateLabel();
         this._updateStatus();
         this._updateMenu();
+        this._addToRecentIcons();
     }
 
     _updateClickCount(event) {

prefs.js

@@ -30,7 +30,7 @@ class AppIndicatorPreferences extends Gtk.Box {
             margin_bottom: 30,
         });
         this.custom_icons_vbox = new Gtk.Box({
-            orientation: Gtk.Orientation.HORIZONTAL,
+            orientation: Gtk.Orientation.VERTICAL,
             spacing: 10,
             margin_start: 10,
             margin_end: 10,
@@ -267,7 +267,39 @@ class AppIndicatorPreferences extends Gtk.Box {
         customTreeView.insert_column(customAttentionIconColumn, 2);
         customTreeView.set_grid_lines(Gtk.TreeViewGridLines.BOTH);
 
+        const iconIDListStore = new Gtk.ListStore();
+        iconIDListStore.set_column_types([
+            GObject.TYPE_STRING,
+        ]);
+        const iconIDListTrack = [];
+        const iconIDTreeView = new Gtk.TreeView({
+            model: iconIDListStore,
+        });
+        const iconIDTreeViewColumn = new Gtk.TreeViewColumn({
+            title: 'Recent Indicator IDs',
+        });
+
+        const updateRecentIcons = () => {
+            const iconIDs = this._settings.get_value('recent-icons').deep_unpack();
+            iconIDs.forEach(v => {
+                if (!iconIDListTrack.includes(v)) {
+                    iconIDListStore.set(iconIDListStore.append(), [0], [v]);
+                    iconIDListTrack.push(v);
+                }
+            });
+        };
+
+        this._settings.connect('changed::recent-icons', updateRecentIcons);
+        updateRecentIcons();
+
+        const standardCellRenderer = new Gtk.CellRendererText();
+        iconIDTreeViewColumn.pack_start(standardCellRenderer, true);
+        iconIDTreeViewColumn.add_attribute(standardCellRenderer, 'text', 0);
+        iconIDTreeView.insert_column(iconIDTreeViewColumn, 0);
+        iconIDTreeView.set_grid_lines(Gtk.TreeViewGridLines.BOTH);
+
         this.custom_icons_vbox.append(customTreeView);
+        this.custom_icons_vbox.append(iconIDTreeView);
 
         cellrenderer.connect('edited', (w, path, text) => {
             this.selection = customTreeView.get_selection();

schemas/org.gnome.shell.extensions.appindicator.gschema.xml

@@ -45,5 +45,10 @@
       <summary>Custom icons</summary>
       <description>Replace any icons with custom icons from themes</description>
     </key>
+    <key name="recent-icons" type="as">
+      <default>[]</default>
+      <summary>Recent icon IDs</summary>
+      <description>List of recently encountered icon ids</description>
+    </key>
   </schema>
 </schemalist>