Normally I run x2x to a second display on my right.  With Galeon on that
display, if I drag a link from Galeon, and the mouse slips off the left
edge back to the main display, the second display becomes confused in an
odd way;

- clicking on a window no longer brings it forward,
- using an Alt/mouse-drag to move the window fails.

Restarting x2x, Galeon, or the window manager, does not fix the symptom.
The only solution found so far is to restart the second X server.

x2x is started as follows;

% x2x -from :0 -to right:0 -east

Window Maker is the window manager on both displays.

Detailed examination of the X events using xev shows no apparent
difference before and after the confusion begins.

Package versions on the right:0 display ...

ii  galeon  1.2.5-0.woody.1
ii  wmaker  0.80.0-4
ii  xserver-xfree86  4.1.0-16

I'll try the -buttonblock option to see if it fixes the problem.