Inconsistent interaction with style editors

[aaime]

The style editor popups work so that you confirm your choices by closing the window.
This is bad because of a few reasons:
- desktop apps associate the window close button with "cancel"
- there is no obvious way to reset any change you made
- contrary to style popups, the main style editor popup has an explicit "save" button to actually apply the style

Imho having explicit apply/cancel buttons would be better (you can use icons if you think they take too much space in the window?)

[tschaub]

This is addressed now (with save/cancel button on rule panel).