lightdash: Preferences window freezes after opening dashboard

[Jonas Kümmerlin]

Am Freitag, den 04.09.2015, 17:35 -0700 schrieb Matthew Brush:
> FYI, you can trivially find problems like that by using stronger
> compiler warnings like `-Wall -Wextra -Werror`. That way it will almost
> never compile successfully if you have such bugs in your code.

Nope, the explicit cast will shut up any warnings. 
 
Unless you also make sure the callback has the explicit same prototype as
expected so you can get rid of the cast. Which might have been possible (but not
necessarily better coding style) in this case, but is not universally useful
e.g. when connecting gobject signals.