Allow dragging floating AUI frames by the gripper.

Previously starting to drag a pane by its gripper worked but once it undocked
it was impossible to drag it by the gripper any more which was annoying for
the user and unexpected.

Fix this by ensuring that we move the correct top level window and not the
child window when dragging floating panes.

Closes #13177.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67751 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/aui/framemanager.cpp

@@ -4623,6 +4623,15 @@ void wxAuiManager::OnMotion(wxMouseEvent& event)
     {
         if (m_action_window)
         {
+            // We can't move the child window so we need to get the frame that
+            // we want to be really moving. This is probably not the best place
+            // to do this but at least it fixes the bug (#13177) for now.
+            if (!m_action_window->IsKindOf(CLASSINFO(wxAuiFloatingFrame)))
+            {
+                wxAuiPaneInfo& pane = GetPane(m_action_window);
+                m_action_window = pane.frame;
+            }
+
             wxPoint pt = m_frame->ClientToScreen(event.GetPosition());
             m_action_window->Move(pt.x - m_action_offset.x,
                                 pt.y - m_action_offset.y);