I even can't see the buttons of the dialog. This is the same behavior in both Windows and Ubuntu 10.10.
That's why I said its an improper design of the dialog itself then. the constructor should make everything needed/possible to properly position the dialog initially. Then
PlaceWindow may adjust it to the users needs in case of multiple monitors.
For the debugger settings pane I see two drawbacks in its contructor:
1.) its wxSmith based, but sets:
SetMinSize(wxSize(600, 600));
SetSize(wxSize(600, 600));
manually -> no good style.
2.) it does not center itself on the parent (if any).
Both should be adjusted using wxSmith. Than you should be happy.
The same applies to all other dialogs that do not behave / position correctly.