Bit of a strange bug for you here! Exactly the same as Seth was having with the previous BETA, where the OSK would not work when planning a route, until the upper address window has been closed by clicking [X].
I've done some testing on this, and for some strange reason, when I run D3 from a shortcut on my desktop, I get this problem. When I run from the shortcut in the DestinatorApps folder it works fine.
I've tried recreating the shortcut, but it doesnt help! It also does not matter if I have Full Screen, maximised or normal windows.