XFCE: last menu entry gets displayed in bold instead of application name

I noticed the following behavior on XFCE with vala-panel-appmenu installed and configured to display the application's name in bold: Open an application with some menu entries (e.g. xfce4-Terminal). Open another application with some menu entries (e.g. GIMP). Terminate that second application by closing its window or pressing control-Q or selecting Quit from its menu. Now the first application is in foreground again, but instead of the application's name (at the left to the global menu bar) being displayed in bold, the rightmost menu entry is. This reverts to the correct depiction once another application (or the Desktop) is selected (brought to foreground).