I'm using the Awesome Window Manager together with Gnome in Linux Mint. I experience the following problem several times a day:
Suddenly the mouse partially stops working, which means that I'm still able to move the cursor, but any mouse clicks won't do anything. Moreover, the cursor doesn't change when it should, e.g. when hovering over links.
This state doesn't change until restarting the computer or restarting the X server with Ctrl+Alt+Backspace.
Despite this the system works quite normal. (I'm writing this message without mouse at the moment)
I think it's very unlikely that it is the mouse as changing the mouse doesn't change the behaviour.
To me, it feels a bit like some invisible window was put over the whole screen, or some application "captured" the mouse and didn't release it, but thats only speculation.
I even tried it via TeamViewer, and it shows the same behaviour -- moving works, hovering and clicking does not.
I should mention the problem is global, not limited to any special program.
Now I know when the bug occurs exactly: If I click in a Gtk application (like Nautilus, Gedit, Ubuntu Software Center) somewhere in the menu bar or the toolbar where no menu or button is (e.g., right of the "Help" menu in Nautilus), then this bug occurs. If I close the corresponding application, it goes away.
I'm going to start a new thread for this.