Xcode 12.2 on Big Sur: Crashing when opening Behaviors pane

My MacBook Pro 16" (2020) crashed during installing Xcode 12.2.

UPD: solved. It was an issue on external Apple monitor. If I use xcode on laptop screen, all good

I have the same now but have crash immediately after clicking Xcode > Preferences

Same issue here,

Code Block ProductBuildVersion: 12B45b
Crashing on exception: The window has been marked as needing another Layout Window pass, but it has already had more Layout Window passes than there are views in the window. 
<NSPanel: 0x7fed210721d0> 0xd4a (3402) {{-6175, 1240}, {830, 552}} Behaviors en

On Macbook Pro 16-inch 2019 , macOs Big Sur 11.0.1 & xCode 12.2. Crashed every time you trying to open ( Xcode > preferences , Product > Scheme > Manage Schemes, etc ...) on external display. If you do this ,in laptop screen works fine.

Similar issue with Xcode here:

1) Displaying on the MBP's built in screen, the Preferences window opens without crashing.

2) Try the same on either of my two external, non-Apple monitors, then Xcode crashes.

My MacBook pro 13" (running Big Sur) is crashing when I try to update Xcode from 12.0.1 to 12.2.

I tried to update Xcode 3 times from app store; and every time my mac crashed.

Does anyone knows how to solve this issue?

My MacBook Pro (15-inch, 2018) after Update Big Sur 11.0.1 and try install Xcode 12.2 from Apple Store, crashing in every 4 times. I stopped in my work :(

As others have noted, this behavior also only seems to happen for me when using XCode on an external monitor, not if XCode is used on the MBP monitor. It seems like Big Sur has numerous little compatibility issues with external monitors (I was having bad flickering issues and it seemed to be a conflict with a Wacom tablet driver). I sort of wonder if it's a change they made in Big Sur to accommodate M1 as M1 can only handle one external (I have two). Funny thing is, it only crashes when clicking "Behaviors" when I have both externals connected, but I tried unplugging one external and using only one (so as if I had an M1) and it crashes on Preferences alone. I opened XCode and clicked Preferences > Behaviors to crash it a few times just to send a few reports hopefully they notice lol.

I have the same issue when using Xcode with an external monitor. The app starts slowing down and sometimes it freezes the entire OS. I’m using a MacBook Pro 16” 32GB i7. The situation improves if I close the lid though.

I do have this exact same problem. I tried this on both Xcode 12.2 (12B45b) and 12.3 beta (12C5020f).
I tested this on Macbook Pro (2020, 32 GB RAM)

• Open Xcode on external monitor

• Open Preferences tab -> Crashed

• Open Xcode again on external monitor, dragged it to build-in monitor (macbookpro)

• Open Preferences tab -> OK

• Drag Xcode back to external monitor

• Open preferences tab -> Crashed

??!!!
Please fix. Thank you.

Xcode 12.3 big sur 11.1
previews are crashing frequently

Yes, Xcode 12.3 still has this issue. Filed a bug report with Apple.

Now deactivate "Main Thread Checker" in your Xcode project: Edit Scheme -> Run/Test -> Diagnostics -> Uncheck Main Thread Checker.

Same problem, filed bug report. Running Xcode 12.3, BigSur 11.1.

yes i had that problem since the first version of xcode12 and it's still there in 12.3
it seems to be a problem with secondary monitor. when i drag xcode back to the main monitor of my macbook i can work with preferences with no problem but behavior tab when on second monitor causes it to crash.

I would say it's not only an Xcode problem (but yeah, I have the same problem when I try to open the 'behavior' tab in preferences Xcode crashes on the external monitor. I've also noticed the same problem with the Wacom software. When I try to move 'Wacom Desktop Center' to an external monitor it also crashes with the same issue but when I use an external monitor as a main monitor application window can be displayed without any problem. It crashes only when I try to move windows from MBP built-in monitor to the external one (only one direction, the opposite works fine).

Anyway is there any update on this the issue persists for over a month already and I would say it's a major one.