Well you may have an external USB mouse but that doesnt mean that the built in mouse tracking system has been automatically disabled so make sure that you have disabled the built-in feature (if it is a mulfunction of the suggested key due to vibrations as sugested above)
Window Manager is discontinued, for WLM try the new, Enhancer for contact list docking, auto-hide, hide taskbar button, remove button flashing and remember keyboard layout in conversation windows
/ 
