Targeting bars and the action not being recognized

[Veranis]

I've been having this problem since I arrived here in September or October. I always just kind of accepted it and dealt with it without really pursuing a fix, but lately it's really been getting to me.

What happens: when I attempt to complete an action by manually clicking the target on a player or NPC status bar, I often get system messages indicating an invalid target. "Too far away" is the one I often get when casting greater heal my pets, despite them being only 2-3 tiles away from me. It happens during fights and PVP events but I often don't get any messages during these failures. It seems random, and happens about ~5-10% of the time.

As you know, I really enjoy the survival game This "bug" has been the reason for my death in 10 out of the past 20 times I attempted survival, and I've finally became frustrated enough to ask if you have any clue what is happening, and what I can do to fix it. I finally uninstalled UO and reinstalled the UO:LL official client a few weeks ago, thinking it might be the problem, but it's happening just as often now as it was before.

Here's an example video, slowed down 50% so you can better see what's going on. I'm using skill provocation, using a "target closest grey" hotkey (you see it when the mob beside me highlights grey), and then manually clicking another mob's bar. It happened twice in a row today on two different status bars, and I was very deep in the match so it was especially discouraging.

https://www.youtube.com/watch?v=Y6jYlUdtLlg

I believe there is something going on in my client that is making the bars transparent. I suspect this because sometimes I have bars hovering over my inventory pack, and when I click to drag the bar away to another position on my screen, I actually end up dragging an item out of my pack, and the bar remains in the same spot.

I know Bloom has had this problem during some 3v3 fights we did. He was having problems with his heals not going through. I've had this same experience during CTF on a few occasions trying to heal team mates. It only happens when clicking the bar; it doesn't happen when using LastTarget or other various target hotkeys.