Bug#952117: Fixed in 0.4.12

[Amr Ibrahim]

This is fixed in 0.4.12.

Drawing 0.4.12
    Closing a tab doesn't trigger errors anymore (#193, this bug was introduced 
by 0.4.11)
    Syntax has been updated to python3.8 (#190)
    The app.quit action asks confirmation if modifications are not saved (#191)
    The "save" dialog opens by default in the user's images directory
    The app.quit action asks confirmation if modifications are not saved (#191)
    The preferences dialog now looks better with Cinnamon, Xfce and MATE