Hum. I been using roll-up and down to change elevation that did not help. Does clicking do more than roll-up, roll-down. Wish I could remember the map name so you could see what I am talking about. Basically I started at the top of the map and when I took out the enemy at the bottom of the map the building spot was at the very edge under the hud. With much effort I was able to click on the very edge of it to build.
