We've fixed a couple bugs, #328035 and #333222, which can occur in situations sort of similar to what you've described. I notice you reported this bug against the beta xserver which doesn't have either of these fixes - please retest after updating to xserver 2:1.6.0-0ubuntu6 and see if you can reproduce the issue.
We've fixed a couple bugs, #328035 and #333222, which can occur in situations sort of similar to what you've described. I notice you reported this bug against the beta xserver which doesn't have either of these fixes - please retest after updating to xserver 2:1.6.0-0ubuntu6 and see if you can reproduce the issue.