Xinerama hiding the cursor in the wrong screen
Submitted by mon..@..eal.ca
Assigned to Xorg Project Team
Created attachment 100487 screen snapshot
Emacs by default hides the X11 mouse pointer/cursor while the user is typing text. It recently changed the way it does so, by using the XFIXES extension. This apparently bumps into a bug in the Xinerama driver:
- I start "emacs -Q" and place its window in the right screen.
- The mouse cursor is above the Emacs window.
- I type "a".
- Emacs asks the X server the hide the cursor, but it's "undrawn in the left screen instead" (i.e. a square blob is drawn at the corresponding place in the left screen and the drawing of the cursor is still present in the right screen).
- I move the mouse a little: the previous cursor drawing is left along and a new mouse cursor is drawn at the new position.
- repeating this "type text + mouse mouse" I can end up with many ghost cursors on the right screen and correspondingly many "square blobs" on the left screen.
Of course, doing something such as switching workspace in my window-manager will redraw everything, which will get rid of those display artifacts.
This system is a Fit-PC2 (with the dreaded gma500 GPU) plus a displaylink USB->DVI adapter, running Debian testing. The window manager is "ctwm".
See attached a copy of my Xorg.0.log as well as a screen snapshot.