"partial" refresh causes a full (without black flash) refresh on
Kindle (which uses REAGL mode for partial refresh). This causes a
full redraw of widgets, which is a bit distracting with some of them:
- dictquicklookup: when showing next definition
- infomessage: when displaying a new one (Wikipedia Save as epub)
Also fix bottom menu, that even when closed, would still register
bottom area as dirty: this would cause top menu navigation to
cause a full partial refresh, only noticable on Kindle.