Comment 51 for bug 658538

This affects me too. Using Ubuntu 11.10 32-bit, GNOME fallback session, on a Sony VAIO 2.2 GHz, 2 GB RAM. Seems to happen more frequently when CPU load is high, but also happens when no GUI apps besides the desktop session are running. I'm using a generic external USB mouse ("ValuMouse Optical, Model # K64381"). It doesn't seem to matter whether I plug it directly into the computer or whether it's going through a USB hub.

Commenting here because this NEVER happens with the built-in trackpad. If I didn't hate using a trackpad so much, I'd stop using the mouse entirely.

I see this as being a SERIOUS PROBLEM. Not only does it break the user's fundamental expectation of mouse responsiveness and expose really annoying underlying problems, but having the mouse suddenly stop functioning has really, really problematic consequences at certain times. For instance, when it happens while trying to drag a message from my Thunderbird in-box to a folder, if the mouse stops functioning while I'm dragging it past another folder name, Thunderbird happily assumes that I actually let go of the button over the other folder. Which, if not noticed, breaks my ability to manage my email effectively. Similar problems (desktop manager assumes I let up on the button when the mouse stops responding) apply to basically every application that uses dragging as part of its user interface.