ok. sorry for this stupid post. i read your help about ITrayIcons.
there it is written that the visibility is only changed temporarily.
You can access the visibility change of the tray icons by using the following methods. A hidden tray icon is automatically shown again in the moment when the ITrayIcon instance gets freed. That means the visibility is only changed temporarily.
but is it possible to hide/delete a trayicon and show it after a certain time again ?
It's possible, you just need to make sure that the ITrayIcon instance for which you called "Hide" doesn't get destroyed. That means, you need to store it in a global variable or list or something like that.