Confirmation for closing the window not visible anymore

On osx 10.9 and TotalTerminal 1.4.6 when I close a window in visor mode there not becomes a confirmation box visible anymore, but the tab doesn’t close either. The cross in the tab to close the terminal becomes a ‘circle’ when a process seems to be running and does nothing when pressed anymore. This behaviour has changed either since Mavericks or with a recent update of TotalTerminal.

Expected behaviour: get a confirmation box when trying to close a visor tab.

The expected behaviour was restored after a reboot. Stopping / uninstalling / reinstalling TotalTerminal didn’t change it, but a reboot did.