Here is a bug.
Setup: 2 monitors
Left monitor (monitor 1): 4K display (3840 × 2160)
Right monitor (monitor 2): 1920x1200
Editor is run on Monitor 1 with settings -enablehighdpi via shortcut (“C:\Program Files (x86)\Epic Games\4.15\Engine\Binaries\Win64\UE4Editor.exe” -enablehighdpi); windows scaling is disabled.
When popup menu is too wide and goes to monitor 2, then menu starts jumping from left to right, right to left trying to reposition itself. So sometimes it is impossible to select a value, especially if it is a blueprint variable.
Are you using the Widget Reflector or some sort of scaling method for the editor’s UI? Without using some sort of scaling, I’m not able to get this behavior to occur.
That’s correct. 4k isn’t my default work environment so I put together a setup with a 4k monitor and a 1920x1200 monitor. I tried reproducing the same issue shown in your screenshot but the menu just stayed on the 4k monitor without any jittering to speak of. The only way I’m able to get anything like this to happen is by editing the Application Scale in the Widget Reflector. Please note that this is separate from the Windows UI scaling.
Could you upload your dxdiag information and provide any other information that could be different between our setups?
Edit: Also, is this specific to 4.15 or does it also occur in 4.14?
You need to make sure that a menu is a long enough. Issue happens in 4.14 as well (this is when -enablehighdpi was introduced instead of Widget Reflector).
I’m trying to reproduce it on an empty project in 4.15, but that menu shows always properly. A project I’m working on is an upgrade from 4.12 → 4.13 → 4.14 → 4.15 I will keep trying on other empty projects from 4.15.
From looking at the dxdiag you provided, while you don’t have Windows UI scaling enabled, it does seem that you do have some DPI scaling enabled. It’s shown on these lines:
User DPI Setting: 144 DPI (150 percent)
System DPI Setting: 144 DPI (150 percent)
DWM DPI Scaling: UnKnown
Could you try returning these to default to see if that could solve the problem?
For experiment, if I set windows scaling to 100%, then there is no DPI scaling anywhere, and -enablehighdpi flag does not do anything. Everything in the editor is a way too small but works. The same effect I can achieve by running the editor without that flag and disabled scaling, but with windows text scaling set to 150%.
I believe the problem is in editor’s scaling: sometimes it does scale properly but does not properly find menus positions, that is why it is jumping. As you said before, you could achieve the same problem with Widget Reflector as is does the same exact scaling as -enablehighdpi flag.
By some reason I cannot reproduce it on empty projects, but it does happen on mine and it is very annoying… it does not happen on every menu at that corner, only on particular ones that are too wide. I will try to research more if I can reproduce it on empty projects. If it helps, I can make a video of the effect in my project.
They do seem to be related. As there’s no reason to split the information for this issue between two posts, I’m going to close the other one as a duplicate and we can continue working on it here.
From your last comment, does this mean that if -enablehighdpi is turned on, it is basically allowing for whatever increased DPI you have set in Windows to affect the editor, meaning that it does nothing without those settings changed in Windows? Please keep in mind that anything that is experiencing the same symptoms as scaling via the Widget Reflector is something we likely don’t support. As with Application Scale in the Widget Reflector, it’s outside of the usual and intended workflow.
if -enablehighdpi is turned on, it is basically allowing for whatever increased DPI you have set in Windows to affect the editor, meaning that it does nothing without those settings changed in Windows
It is correct. If I set Windows text scale to 100%, and run editor with -enablehighdpi it will not scale the editor, as where will it scale to? As I understood a whole idea behind -enablehighdpi is to scale text and icons in the editor to settings in Windows (in my case 150%).
Also, I do not use “Widget Reflector”'s scale as it caused a lot of crashes for me when I tested it. Then I figured out -enablehighdpi option for the editor that does not crash.
it looks like I fixed the problem. What I did is: from our project I deleted folders Intermediate, Saved, Binaries and Debug (I noticed that some files in those folders (Intermediate, Saved) were under source control, that could possible explain why some files weren’t upgraded properly). Then I launched UE4 Editor on uproject file, it recreated all missing files/folders, and problem seems to be fixed (at least menus open properly).
