[Unintended behaviour] Deselecting several elements is hard

[12345ieee]

Affected units:
* Unbuilt omni
* Energy mines
* Several less used units

Current behaviour:
* Select an unbuilt omni
* Click somewhere else on the map
* The omni isn't unselected

Why this is a problem:
* Everything else (that doesn't move) deselects with a click on empty space

Expected behaviour:
* After clicking away, the unit deselects