I am running the xserver, libs, etc compiled from the latest git source. I've had this problem for a long time now, using Xinerama in a dual head setup, once the mouse gets into the right monitor, it is not possible to bring it back to the left monitor. Until recently, I had a ATI radeon card, and i could use the merged frame-buffer mode and that did not have this problem. A few days ago I installed a Matrox P650 PCI card, and the problem is back. Unfortunately I could not get the merged frame-buffer to work with this card. I am using the unofficial mtx driver which says that it's unable to find any usable modes for the second monitor. The log file for the Xinerama setup is attached, although I couldn't see anything amiss in it. thanks, Ritesh