When ever I try to set up my F-keys then the entire interface goes missing. I assume I must have hit some "hide/show interface button, but I can't for the life of me find it.
Anyone have any help. It also isn't mentioned in manual, I think.

regards

Check out this post . . . =)

You should be able to just press the F key for the desired result for potions etc. If a right click is necessary to use a skill, i.e. Poison Weapon or Lightening, just make sure you right click anywhere but on the UI. It seems like you would right click the active skill icon on the UI but if you do, the UI minimizes. For a magic skill like Lightening you would right click the opponent you want to attack being careful not to click the UI.

Right clicking on the very thin status bars at the bottom of the screen will bring the icons back.