When using VirtualBox seamless mode and Compiz you may find that other windows from the host start to randomly disappear. This is a partial workaround.
The bug is described in detail here.
The bug is triggered when either the guest Windows desktop is completely visible or completely obscured by application windows. Unfortunately there isn’t much we can do about the latter case, but the former can be worked around by opening a 1px x 1px window in the corner of the screen where it won’t be noticed.
This has already been implemented as a .NET application, but I didn’t want to install .NET in my Windows guest, so I decided to reimplement it using C and Win32. The C version actually came out shorter. You can compile it with mingw32, which is available as a package on Debian based distributions.
You can find my binary and source here.
I must give credit for the idea to this other version.
You can find the original workaround mirrored here.
Thanks to Quintus Leung for the patch which makes the pixel transparent, and therefore less noticeable.
Update 2: This seems to be fixed in Karmic’s VirtualBox / Compiz.