Bug in contact filtering of actions after deleting unique action with that contact

See !489 (comment 5574367) and following comments.

Basically:

Lets say I have a platform with 2 generic platform actions. One has contact A, the other one has contact B. I then filter for contact A - and decide to delete this action. The problem now is that the contact filter seems to be empty (nothing shown) but it isn't. The contact filter for contact A is still active, but as there is action left associated to it, I have no chance to deactivate it.

And:

No filter:

Filter for Marc:

After deletion:

Contact filter then:

Contact filter after I selected myself:

(I think the comma at the end of my contact selection shows that there is one entry more that is somehow not rendered. But I still have no other chance to clear this than reloading the page).

Note: We can assume that this can be problematic for the year filter too.