The IHighliterService used to be launched everytime (see below)

Since the MoveMousecommandHandler is now launched all the time and it referenced the HighlighterService as OptionalTryStart, the keyscroller was also always on.
Fixed it by setting the OptionalTryStart requirement directly on the keyboard's layer, and removing it from the MoveMouseCommandHandler.
Merge branch 'b-2.6.1-fixes'