Virtual desktop scrolls in KDE

[kermitjunior]

Whenever I start KDM (flux, kde, wm), I have a problem with my desktop not matching the size of my screen. There is roughly a 3-4in virtual scroll that annoys the heck out of me.

How do make it so it fits correctly? Also, can you change resolutions on the fly (like in that other OS)?

Thanks.
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