"hidden" windows in unity: high load for compiz?

[Peter Teuben]

Today I had two instances of tasks that did not show up in Unity's task
bar on the left.
This apparently causes a constant high load (~50%) for compiz:

1) Picasa3.exe was running, but the icon had disappeared, and it was
also not visible
     in Super+W or Super+S.  I've seen this before with emacs, and my
solution was
    to start another one, which then suddenly made both visible..... 
but not this time.
    I killed Picasa manually from the task list. This in itself didn't
clarify to me what was
    going on, but the next item was!

2) pidgin only showed a chat window, not the original parent window with
my contacts.
    This despite the fact
    that the icon in Unity showed 2 little horizontal stripes on the
left side of the icon,
    indicating there were two windows.  I could not get this parent
window to shop up.
    As soon as I manually killed pidgin, the compiz load went from 50%
to 5%. Clearly
    something is buggy here.

A load like this already makes a fast i7 based laptop feel like an old
laptop with not enough
memory.

I should perhaps also mention that I install a revamped unity, with the
Dogded Windows bahavior, as described in this link:
   
http://www.ubuntugeek.com/howto-unity-with-dodge-windows-and-minimizeunminimize-behavior-in-ubuntu-12-04-precise.html

peter