I seem to be having problems within this game (don't see it on others) on this PC (laptop) where the mouse seems to be "hyperactive". If I try to select units by click/drag a box, the box doesn't form, or forms late causing some units not to be grabbed. Double clicking a unit selects and deselects all units of that type at the same time. It seems as though its double clicking by default as I get multiple actions from a single click. I don't have it selected in mouse options (where single click acts as double click).
Frustrating as it makes the game unplayable.
Something else I noticed after having been gone a while, WASD isn't panning the camera like the arrow keys do. Seems it used to do that.