In Okular:
Some settings are okular wide, if you change them, they will be changed in all the future okular instances, an easy example is if you change the shortcut for saving from Ctrl+S to Ctrl+Shift+E.
Some other settings are document specific, for example zoom, if you change the zoom of a document it will only be restored when opening the same document again, but not if you open a different one. There's also a "default zoom value for documents you've never opened before" in the settings.
Some other settings like "Continuous View" are a bit of a mess and are both. "Continuous View" wants to be a global setting (i.e. so that if you hate continuous view you always get a non continous view) but it is also restored to the status it had when you closed the document you're just opening.
That's understandably a bit confusing for users :D
My suggestion for continuous view would be to make it work like Zoom, be purely document specific but also have a default option in the settings dialog for people that hate continous view.
I'm guessing this should cover all our bases?
Opinions? Anything i may have missed?
