The Tavern

Hovering over a summoned enemy should highlight the summoning monster, if it's in LoS. Reason being, if you have say, 2 orc high priests in melee range and one of them summons, say, an orange demon, you might want to prioritize attacking the summoner. But, how would you know which orc is the summoner with the current UI behavior?

Doesn't it do that already? With the targeter for ranged attacks and 'x'?

Yes, with a circle around the summoner.

I see, in that case it does (and thanks for the tip). But, when hovering the mouse over the summoned monster or looking with SHIFT+X, it does not. If possible, it would be best to make this behavior consistent so that the circle appears with each of these viewing methods, especially considering the most popular play-style (meleedude) doesn't need to use the targeter in most situations, so players (e.g. myself) could potentially play for years without ever seeing that circle if it only appears with the targeter.