Fix bug where Layer > Open Group didn't update the Timeline rows

src/app/commands/cmd_open_group.cpp

@@ -1,4 +1,5 @@
 // Aseprite
+// Copyright (C) 2022  Igara Studio S.A.
 // Copyright (C) 2017  David Capello
 //
 // This program is distributed under the terms of
@@ -53,9 +54,11 @@ bool OpenGroupCommand::onChecked(Context* context)
 void OpenGroupCommand::onExecute(Context* context)
 {
   ContextWriter writer(context);
+  Doc* doc = writer.document();
   Layer* layer = writer.layer();
 
   layer->setCollapsed(layer->isExpanded());
+  doc->notifyLayerGroupCollapseChange(layer);
 
   update_screen_for_document(writer.document());
 }

src/app/doc.cpp

@@ -267,6 +267,13 @@ void Doc::notifyTilesetChanged(Tileset* tileset)
   notify_observers<DocEvent&>(&DocObserver::onTilesetChanged, ev);
 }
 
+void Doc::notifyLayerGroupCollapseChange(Layer* layer)
+{
+  DocEvent ev(this);
+  ev.layer(layer);
+  notify_observers<DocEvent&>(&DocObserver::onLayerCollapsedChanged, ev);
+}
+
 bool Doc::isModified() const
 {
   return !m_undo->isSavedState();

src/app/doc.h

@@ -115,6 +115,7 @@ namespace app {
     void notifySelectionChanged();
     void notifySelectionBoundariesChanged();
     void notifyTilesetChanged(Tileset* tileset);
+    void notifyLayerGroupCollapseChange(Layer* layer);
 
     //////////////////////////////////////////////////////////////////////
     // File related properties

src/app/doc_observer.h

@@ -89,6 +89,9 @@ namespace app {
     // The tileset has changed.
     virtual void onTilesetChanged(DocEvent& ev) { }
 
+    // The collapsed/expanded flag of a specific layer changed.
+    virtual void onLayerCollapsedChanged(DocEvent& ev) { }
+
   };
 
 } // namespace app

src/app/ui/timeline/timeline.cpp

@@ -1926,6 +1926,12 @@ void Timeline::onTagRename(DocEvent& ev)
   invalidateHit(Hit(PART_TAGS));
 }
 
+void Timeline::onLayerCollapsedChanged(DocEvent& ev)
+{
+  regenerateRows();
+  invalidate();
+}
+
 void Timeline::onStateChanged(Editor* editor)
 {
   m_aniControls.updateUsingEditor(editor);
@@ -4442,9 +4448,7 @@ void Timeline::setLayerCollapsedFlag(const layer_t l, const bool state)
 
   if (layer->isGroup() && layer->isCollapsed() != state) {
     layer->setCollapsed(state);
-
-    regenerateRows();
-    invalidate();
+    m_document->notifyLayerGroupCollapseChange(layer);
   }
 }
 

src/app/ui/timeline/timeline.h

@@ -165,6 +165,7 @@ namespace app {
     void onRemoveTag(DocEvent& ev) override;
     void onTagChange(DocEvent& ev) override;
     void onTagRename(DocEvent& ev) override;
+    void onLayerCollapsedChanged(DocEvent& ev) override;
 
     // app::Context slots.
     void onBeforeCommandExecution(CommandExecutionEvent& ev);