I'm quite new to this jMonkey engine, I have been doing some of the early tutorials, but when I use the SimpleGame Base and run the program, if I choose the LWJGL Renderer all I get is a blank screen until I press F4 to bring up the states, then I can see my display. This problem doesn't seem to happen if I use the JOGL renderer.
its a known bug (that i committed ;))
update from SVN and the problem should be fixed.
thanks