I've installed the 12.0.4 beta on my Dell latitude XT2 and although I can navigate Dash with my fingers, but the Onboard onscreen keyboard does not pop up when I want to search for applications in Dash.
I've also tried Caribou but it gets in the way far too much, it pops up when i want to input in the URL bar in Firefox but does not go away when i want it to! I would also try Florence if it wasn't a dependency hell to compile it.