Comment 100 for bug 195929

(In reply to comment #48)
> The engine can test if the style property is present. Whatever seems to be the
> most sane I will do.

It is a pain to test the style property in the engine. This is because I first need to check whether it does exist (or else all GTK+ applications spew thousands of warnings).

> > (In reply to comment #46)
> Apart from the naming part, comment 41 was telling that we shouldn't set the
> data on the widget if we aren't sure that we effectively can draw directly on
> the canvas. And that we shouldn't set this data only on entries or progress
> bars, but on every widget we can draw (while ensuring that the data isn't
> lying). If progressbar rendering is already "transparent-safe", good (but I
> hope that no theme relies on the progressbar being opaque).

The engine needs the hint to know that it does not need to fill in the background. It should only be read by engines for for this one purpose in my oppinion.

> As for registering the style property on GtkWidget, if it's absolutely sure
> that we won't need it on other widgets, and that it's not a problem if a theme
> tries to set the property when it's non-existent, no problem with me.

Any style property that is set but does not exist is silently ignored.