Description of problem: Extension "system-monitor" by darkxst (https://extensions.gnome.org/extension/120/system-monitor/) provides onmouseover popup information. When this popup is shown, shortcut Ctrl+Alt+L is not working properly. Lockscreen is shown but disappears or gnome-shell crashes. GNOME Shell 3.6.2 Steps to Reproduce: 1. Mouse over system-monitor extension 2. Small pop-up shows 3. Ctrl+Alt+L 4. Locksreen is shown but immediately disappears or gnome-shell crashes
This extension is not available in the Fedora repositories. It's not even part of the Shell extensions provided by the GNOME Project (http://git.gnome.org/browse/gnome-shell-extensions). I suggest you instead to directly contact the developer of this extension, through its Github project page (https://github.com/paradoxxxzero/gnome-shell-system-monitor-applet/). Check also if the issue you encountered is not already reported (see https://github.com/paradoxxxzero/gnome-shell-system-monitor-applet/issues).
*** This bug has been marked as a duplicate of bug 904823 ***