Asset Browser: Activate a catalog when dragging

Without this it's easy to loose track of which catalog you are dragging.
Things feel generally quite jumpy/disconnected, activating the catalog
makes things feel far less like that.
I consider this an important usability fix, therefore I'm adding it to
the release branch.

1 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/editors/interface/tree_view.cc b/source/blender/editors/interface/tree_view.cc
index fcc878c440c..488b3bbb726 100644
--- a/source/blender/editors/interface/tree_view.cc
+++ b/source/blender/editors/interface/tree_view.cc
@@ -550,6 +550,19 @@ void AbstractTreeViewItem::change_state_delayed()
     activate();
   }
 }
+
+/* ---------------------------------------------------------------------- */
+
+AbstractTreeViewItemDragController::AbstractTreeViewItemDragController(AbstractTreeView &tree_view)
+    : tree_view_(tree_view)
+{
+}
+
+void AbstractTreeViewItemDragController::on_drag_start()
+{
+  /* Do nothing by default. */
+}
+
 /* ---------------------------------------------------------------------- */
 
 AbstractTreeViewItemDropController::AbstractTreeViewItemDropController(AbstractTreeView &tree_view)
@@ -714,6 +727,8 @@ bool UI_tree_view_item_drag_start(bContext *C, uiTreeViewItemHandle *item_)
                       drag_controller->create_drag_data(),
                       0,
                       WM_DRAG_FREE_DATA);
+  drag_controller->on_drag_start();
+
   return true;
 }