When a tooltip disappears, garbage is sometimes left behind. This
happens at least with Firefox and with GNU Emacs (e.g. when using
the nXML mode, which displays tooltips in case of invalid values).

I've attached an example of what I obtain.

Control: tags -1 moreinfo

I'm not able to reproduce this with chromium. Does this happen with other
applications? What window managaer do you use? What options do you use to run
xcompmgr? Also, could you please test version 1.1.6 (in sid)?

Cheers

Control: tags -1 found 1.1.6-1

Not just with a tooltip. If I select something in Iceweasel, and drag
it, garbage is also sometimes left behind. If the window loses the
focus or if I take a screenshot, the garbage disappears.

When dragging a selection, I also get errors like:

error 9: BadDrawable (invalid Pixmap or Window parameter) request 153 minor 1 serial 44087
error 3: BadWindow (invalid Window parameter) request 139 minor 6 serial 44088
error 3: BadWindow (invalid Window parameter) request 20 minor 0 serial 44089
error 3: BadWindow (invalid Window parameter) request 15 minor 0 serial 44090
error 3: BadWindow (invalid Window parameter) request 2 minor 0 serial 44091
error 3: BadWindow (invalid Window parameter) request 20 minor 0 serial 44092
error 3: BadWindow (invalid Window parameter) request 2 minor 0 serial 44093
error 3: BadWindow (invalid Window parameter) request 20 minor 0 serial 44094

I can't either.

After running chromium, I couldn't reproduce the above problem with
garbage.

I think with GnuCash too.

fvwm

xcompmgr -c

The above problem with select+drag was obtained with 1.1.6.

Control: tags -1 - moreinfo + confirmed

I can confirm the select+drag behaviour with iceweasel on both fvwm and dwm.

Running in synchronous mode (-S) makes the errors go away (but the garbage
remains) so I guess they aren't really related.

Unfortunately I have been unable to pinpoint the offending code thus far.

Cheers