fix issue, then it wasn't possible to remove functional blocks from
project using right click and popup menu.

The problem is that, PopupMenu was called using IDEFrame object and as
a result item in ProjectTree loosed focus and focus went to IDEFrame.
Therefore later functions couldn't detect which item in ProjectTree
was selected.

import os
from POULibrary import POULibrary

class NativeLibrary(POULibrary):
    def GetLibraryPath(self):
        return os.path.join(os.path.split(__file__)[0], "NativeLib.xml")