Release 1.3.9:
Create a project with two forms. Default form has button, that launches second form as a dialog.
Dragging the second dialog form with the title bar as to move the form’s bottom or right side off screen results in the condition where the dialog form can no longer be moved by dragging with the title bar.
Yes, I can reproduce that. The body scrolls up but all dom properties remain unchanged. It seems to be a bug in the browser(s), but I know what caused it pop up now and will be fixed in the upcoming update.