Hi Carlos,
Thanks a lot for your answer.
For information, I upgraded PySide package to version 1.1.1 which
solved the problem but with many warning messages like
X Error: BadCursor (invalid Cursor parameter) 6
Major opcode: 2 (X_ChangeWindowAttributes)
Resource id: 0x3
X Error: BadCursor (invalid Cursor parameter) 6
Major opcode: 95 (X_FreeCursor)
Resource id: 0x3
Cheers,
Paulo