Ive been using udk for years now but just by mistake when i was in the editor i pressed the º key
http://www.leccionespracticas.com/wp-content/uploads/2012/11/teclado_apple_ES.jpg (ignore the arrows grater than one from the photo) just the one over the tab key.
And it looks like if you hold it, it activates realtime+ displaying a 3d cube below the mouse cursor(which i supose its the hidden representation of the 3d mouse used for extruding/subtracting)
Ive found it to be interesting(not of any use)but still one more fun fact to know.(or a bug for me :rolleyes: )
Cheers
Hey Frank!Havent thought about the keyboard(the one im showing i think is a mac one)But you shoud just press and hold(in editor mode) the key placed over the tab one.Either way,you are not missing anything special 