Comment 3 for bug 305879

It is reproducible. You can make as many boxes as you want, and, after clearing them, more boxes can be created.

In order to reproduce this:
 - Connect two cursor-controlling devices (such as two mice, or a single mouse and touchpad)
 - Left-click and drag with one device, creating a selection box
 - While still holding the button down, left-click the other input device
The old selection box (the one created from the first click) will remain there.

I am not running Compiz or any special-effect software (besides the Nvidia driver).

I have tested this on Hardy Heron, and I cannot recreate the bug. It happens only in Intrepid Ibex.