! Needs testing / verification !
The cost of diagonal movement is believed to be of 1.5 OR square root of 2 = 1.41.
As the decimals of AP are not shown, one can not see how much a diagonal movement is going to cost, apart from moving the cursor around, or installing mods.
The first diagonal movement of an agent will always show to cost 2 AP. (If one agent has 10 AP, he will show to have only 8 left after the first movement, whereas he will have 8.5 left).