Very minor one this, but I think that it’s still worth mentioning.
Open the orders list.
Begin clicking through the orders, as if you were browsing the descriptions while deciding which you want.
Click between two orders fast enough that it would be considered a double click if done on the spot.
If your mouse pointer didn’t travel far enough, the order you just clicked on will be added.
If you go from the bottom of one order icon to the top of the next between clicks, no order is added.
It seems to be a little bit hit and miss, but that seems to be related to how far the mouse pointer is moved.
In other news… De-selecting ships still leaves the last selected ship in the orders box on the left, but the box is partially disfunctional.