Without changing something, the start-program-menu does not open anymore in Gnome.
You can click, but there no window opens and there is no error shown up.
It seems, that Gnome Web Photo crashes are causing this.
At the moment the menu is working again.
How can i disable an automatic start of gnome web photo?
You can disable programs from launching at start-up in Gnome from the Control Centre. Go to the system settings in Control Centre and click on sessions. Now you will have a list of applications that launch when Gnome starts up. You can de-select the ones you do not want at start-up (in your case gnome-web-photo).