#19 No refresh of wallpaper in certain instances

[FWishbringer]

Hardware Configuration:
Two monitors such that Control Panel-Screen Resolution reports Monitor 1 is on the right, and primary, and Monitor 2 is on the left.

Using Explorer Desktop

If the user sets Monitor 2 to primary in Control Panel-Screen Resolution, the theme manager will change only the wallpaper for the new Primary monitor, and not the no-longer-primary monitor.

Note:
When switching back to the previous monitor as primary, both screens update correctly.