Hi Dave,
For some reason, the wxCalendarBox control was not working on linux (i.e. Ubuntu).
I found that - wxWidgets has already provided a class for that. (wxDatePickerCtrl).
As per our conversation, I have modified the code to use the wxDatePickerCtrl instead of wxCalendarBox.
Please find the patch for the master branch.
I have made minimal changes to work this control as per our expectation.
I think - this is a bug, so we should apply this to REL-1_12 and REL-1_10 branches too...
If you want, I can generate the patches for them.
Please review this patch and give your comments.