Compiz + XFCE panel, restoring minimized windows not working

[sasq]

I have XFCE and Compiz Fusion installed on a fresh Gentoo installation on my laptop.
For some time everything worked like a charm.
But yesterday I noticed that when I minimize windows, I cannot restore them by clicking their buttons on the XFCE panel.
When I click them, nothing happens, and they just start blinking, but no window appears anymore.
Right-clicking and selecting "unminimize" sometimes work, and other times doesn't work either.
The only thing that can restore such a window is Alt+Tabbing through all running programs and selecting the minimized one.

I cannot figure out why does it happen. After launching XFCE by startxfce4 it usually works OK for a while, but something triggers this bug after some time and the windows start behaving as I described above. I think the order in which I minimize them and try to restore later can somehow trigger it, since the bug usually activates when I minimize several windows and try to restore them in a different order than I minimized them. But I couldn't manage to reproduce it in a reliable manner yet.

Any ideas what could be wrong and how to fix it?
I can provide any info about the configuration if needed.
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SasQ