On the attack phases both fast and slow in version 1.10 v2 you can select targets that don't exist in the middle boxes.
To reproduce:
Pick the plane to attack.
Move the cursor around the middle boxes, the cursor changes to an up arrow and you then click, which causes a red circle to appear.
It's just a question of a very tedious process changing it to not do this. It won't allow you to attack it or do anything with it, so its just a minor thing. [:)]
Derek
Lead Programmer of Hornet Leader PC
Mindtoy Games - Unique Strategy/Board/Card games for the PC - mindtoygames.com