Hi Jos,

You may try to send a message to the system tray window making it to redraw itself or some of its children.

DECLARE INTEGER SendMessage IN user32;
	INTEGER hWnd,;
	INTEGER Msg,;
	INTEGER wParam,;
	INTEGER lParam

At this point I'm not sure what message (or messages) to send: WM_PAINT, WM_SHOWWINDOW or some others.

The question is how to find hWnd for the system tray window. This is easy. The window has a very distinctive class name -- Shell_TrayWnd:

hTrayWindow = FindWindow("Shell_TrayWnd", Null)

On this page http://www.news2news.com/vfp/?example=336 take a look at a picture in comments, a fragment of Visual Studion Spy++ screen. It gives you an idea about the windows hierarchy inside the Tray Window.