Exception Type: Nil Object Exception

1: Function MainWindow.MainWindow.Event_CancelClose( MainWindow.MainWindow, boolean ) as boolean

User description of above error trace:

Closed a planfile, did not notice the "Save - Yes/No/Cancel" popup as it was not displayed on top of the planfile window but on top of another planfile's window. Hit close again and chose "Yes" to save the planfile which resulted in this exception.

Fixed.