When the widget "Window Menu Bar" is in the panel and I launch the application FlameRobin (Firebird database administration tool), memory and cpu used by plasma-desktop start to grow rapidly until plasma stops responding and I have to kill the process.
The problem is always reproducible.
My suspicion is that the problem is related to wxWidgets library used by FlameRobin, although other programs that use this library does not appear to causing the problem.
Perhaps the problem could be related to some specific version of the wxWidgets library.
The version of FlameRobin in use is the "0.9.3.2220 Unicode" that uses the wxWidget library version 2.8.12
OS is Kubuntu Quantal 64bit
Remove Window Menu Bar from the panel and the problem goes away, but this isn't a solution, obiouvsly..
Sorry for my English, I hope that the problem has been clearly explained.
Forget my indication on wxWidgets.
If I launch Filezilla that is based on the same version of wxWidgets used by FlameRobin, it works without issues with window menu bar.