Code review comment for lp:~tomasgroth/openlp/mupdf

> Looks great but in final testing came up with a problem
>
> Settings dialog - the tick box seems to use all three states.
>
> Tick box and type rubbish in to the file box.
> Press cancel and you get an error message - Not Correct.
> When the dialog reappears the light grey tick is present - Not correct.

I can't see any easy way around this if I want to validate input in the settingstab, and display an error without saving.
As I see it we need to add a "validate" method to the SettingsTab class, which would then be called before "save" is called. That way my onchange-validation isn't needed.