Created attachment 266923 [details]
Minimal example

The documentation says "Widget state pseudoclasses may only apply to the last element in a selector." However, it would be nice if this were not the case, for two reasons:

1) it is legal CSS.
2) since GTK 3.10 widget states don't propagate to child widgets, so if you want to select a GtkImage inside a prelit GtkButton you have to manually propagate the state flags, which is annoying.

The attached minimal example illustrates the problem: the desired behavior is that the icon inside the "I should turn red" button turns red on mouse-over. The "I do turn red" button illustrates the current way of implementing that behavior.