You NEED to make it possible to use WASD in the designer. Here is a basic keyboard layout (you may need to open these in a new tab or something to see them):

I could easily have my left hand on WASD and my right hand on the mouse, moving around and clicking when I need to. Then, when I needed to test the level, I could easily move my left hand down to Shift Z X and C, and my right hand to the arrow keys.
Like this (with "1" being in the designer, and "2" playing/testing:

But right now you have to be all the way on the right side, with left on arrow keys and right on mouse, moving all the way over to Shift/Z/X/C and right hand to the arrow keys, like this (same thing with the numbers):

So we need WASD to work in the LD.
(suyo and the rest, don't kill me for using windows (and google). and being terrible at writing on a computer.)