[Fixed] Dialog window hide behind of the main window by LMB click.

[dgud]

wxWidgets Mac variant have some problems with the handling of dialogs,
I have tried to workaround that previously, but removed the workaround in 2.1.2 because
I thought it worked ok and the workaround caused other dialog problems.

If you got an error dialog when in another dialog, the error dialog came behind the first dialog
and you didn't see it and the whole wings app seemed to hang.

I will do some more testing, it might be that me and Björn have different wxWidgets versions and
it is fixed in the version I use but not in the version Björn uses.