I have removed the Move ability from my Stalker, though it still moves toward a target when I order him to attack it.
Any ways to prevent him from moving at all, but still attack anything in range?
None.
If you have a 'Move' button in his command card, try getting rid of it. If all else fails, make his acceleration/movement speed 0.
None.
I do stuff and thingies... Try widening and reducing the number of small nooks and crannies to correct the problem.
Add a buff that sets movement speed to 0 or better suppresses movement?
So basically, behavior: warp prism - make immobile
edit:
use this to disable movement for only a few units. Changing movement speed with triggers might work, too...