As of 11.1.7, I have a white square that appears on the far left of my screen, mid height, whenever I left click the playing field. It is approx 120px in height and width. It disappears when I let go of left click again.
All addons are disabled.
It seems to cause no harm other than being obnoxious and unnecessary.
Happening to me also and I don’t use add-ons. It happens on the character select screen as well.
Any time I hover my mouse over something that is clickable, the white square will randomly pop up for a second.
It’s quite mysterious. Do you have a gamepad plugged in by chance? Or are you running an older version of windows? (trying to find some commonalities in our situation).
Same here. Thought it was Ad don related from previous forum threads, but I suppose that is not the case. My spouse doesn’t use any add ons, and she has the box appear when clicking anything as well.
are you all on Windows?
is it maybe a windows notification that is bugging out?
Don’t know what a gamepad is, so no. Windows 10, all up to date. Nothing has changed on my PC for a while except for the game update this morning.
Yesterday night the game was running fine, today it has a random white square.
The patch broke something.
Yeah, yesterday was good. Windows 11 here. At fits I thought it was a desktop app coming through for some reason because of the location, but i moved the apps and its still there. I even went and downloaded the recent nvidia driver. Idk what it is.
Some people in game said they had a green square, not white.
I have been having this issue for at least a year… before by switching to directX 11 in graphics resolved the issue. Now however, it is appearing there too, at least on my end. But try that on your end and see if it helps…
I think this has also broke my drivers in some way. I keep getting black screens and everything loads back in really weirdly.
I am here to add to list of players who are dealing with this issue. It only appears when I left click the screen. What is interesting is that in screenshots, it doesn’t appear. I thought it was the reflex analyzer, but I disabled that in GeForce Experience. Then I uninstalled Experience. All was fine before the update.
Ok I installed: GeForce Game Ready Driver 576.80 | Windows 11. It came out this AM and seems to have resolved it for me.
Happening to me too. All addons disabled and even tried to repair the game. No luck.
Happening here too. Tried repair, updating addons, deleting all addons, tried changing from directX 11 to auto detect and back, nada so I guess I’ll play again once blizzard resolves it because it drives me to a madness shadowpriests and void elves will understand - Just got my computer repaired, and I don’t wanna end up taking a bat to it in frustration 
Only reason I haven’t been driven mad by it is I’m unsubbed for the summer. I just noticed it while logging my level 11 to say hi to my guild.
Hopefully they get it fixed soon. Every part of the game is so complicated now they seem to have difficulty keeping the quality up.
I recall this issue happening with DX12 a while ago and now its isolated to DX11 for me. If I swap to using DX12 the white box appearing on mouse click stops but the game runs worse.
I’m running Windows 7 so I cannot update drivers.
The game was fine before a couple updates ago. Hopefully whatever this is can be fixed/reverted. It’s pretty annoying and distracting.
July 9th Update–
The white square persists.
Further details: It happens even on the title screen, the character select screen, but does not appear on loading screens.
August 5th update (Patch 11.2)-- White square still persists.
Blizzard, tell you what. If you fix the white square I’ll buy Midnight. If not, how can I be assured of the quality of ANYTHING going forward?