

I have the exact same problem with my 16-inch 2019 macbook pro. This allows me to use any scaling value with the rotated monitor and the dead zone/offset issue goes away. So far the only thing that fixes it for me, other than running the display at default (1080p) or native (4k) scaling is to us my iPad as a Sidecar display. I too have noticed that the display shows an incorrect resolution in the system reports of 2880x5120 when at a scaling value in between default (1080p) and native (4k). This only occurs when the display is rotated in MacOS 90/270 degrees and when the display is not at default scaling (1080p) or native scaling (4k). The mouse clicks do not register where the mouse appears to be.

The monitor has this dead zone on the right side where the mouse cursor disappears and reappears but then interactions are offset by a large margin (1.5 inches or so). The issue occurs on an LG 27uk850 (2560x1440), and was not occurring with the same monitor setup when using my 2018 15" MacBook Pro. Same problem here with a 2020 iMac 27-inch and Radeon 5700 in MacOS Big Sur 11.0.1. Only solution is connect the display usb hub via the SS-USB connector and not via USB-C which is ok for me as its on the far right and I don't move the mouse that much in that area. Only thing is that macOS still thinks that the benq connected via usb-c as well, is another display and the mouse would be able to move off screen (main) to that "display". If I move that 3rd "display" to the right of the main display (Benq connected via eGPU), then the problem is gone. When I leave this 3rd "display" to the left of the dell (in the arrangement), then the problem appears. In the moment I connect the benq via usb-c, macOS thinks/detect the benq as another monitor and adds it to the arrangement.

I connected the benq as well via usb-c to the computer so I have access the usb-hub and sd reader on the benq display. I have an egpu connected to the computer and from the egpu I connect both displays. So I have a Benq sw271 as main display, a Dell 2415 with 90 degrees rotation to the left of the benq and the laptop MBP 15'' behind that dell display. To shorten this post I've placed screenshots and System Information within Spolers.
#MOUSE CURSOR DISAPPEARS AND REAPPEARS PRO#
Newer monitor with USB-C port, directly connected to Macbook Pro 16" with USB-C to USB-C cable.

I didn't check each scaling option, but I am assuming any scaled option (other than Most Space) in Portrait mode is going to be affected by this bug.Ĭonfirmations of the same behavior might help. So while it's not a fix for those who need scaling, the point is that it pinpoints the problem, so we might get some attention to this matter. But for many people, this means the text is too small. Reopening System Report showed a much more sensical number, 2160 x 3840 (4k, backwards, since it's portrait). When I set the box all the way to the end, " More Space", my display and UI went into true 4K resolution, and the offset problems were gone. While having the problem, I was set to the 4th box, the one before the last. I went to System Preferences -> Displays, my resolution was set to " Scaled" and under that are 5 boxes, from " Larger Text" on the leftmost, to " More Space" on the rightmost. So I instantly got the idea that this was a bug with UI scaling. While gathering specs to post on this thread, from " System Report -> Graphics/Displays", I noticed the reported resolution was way off from my actual 4K resolution: 3600 x 6400. I have a 4K monitor portrait rotated (270 deg), and I was having issues with the mouse clicks being offset at the bottom of the screen.
