Flickering in editor

Starting at 4.17 and now into 4.18.1, occasionally the editor will badly flicker. This is only the main editor window, if I open a blueprint that isn’t pegged in the main window, it will not flicker. Other questions about similar problems were answered that the system was below minimum. Mine meets and exceeds all minimums (3ghz Xeon 8-core, 32GB ram, High Sierra, XCode 9, has the dual 700s for video, btw, it is a Mac). I run dual monitors and perhaps that is related in some way. I thought I’d report it. I can usually get it to stop after closing unreal and opening it again. When it happens, it is for the entire session starting when unreal opens and until I close it. No other screen anomalies in any other app.

It is pretty dramatic while it’s happening. Not really usable.

Hi eagletree,

As you mentioned, we have had a few reports of flickering occurring in the Editor on Macs. Unfortunately we have never been able to reproduce it ourselves so we are not yet certain what causes it to happen. The Mac that I have tried to reproduce this with only has a single monitor, but we have several Macs that are used regularly that have multiple monitors, and none of the people who use those computers have experienced this flickering.

We are still looking for more information that may help us to reproduce the flickering here and narrow down what could be causing it. If you have any additional information that you can provide, it would be very helpful. Have you seen the flickering occur in multiple projects, or is it only in one project that it happens?

Hi @ C

I have flickering on PC. It happens when menu list extending bottom of editor like a here:


on screenshot this is not visible, but flickering is insane.

when menu is whole on editor, no flickering:


As I remember, it starts from 4.18. I had this problem in older version too, but I not remember number and after some update it was correct - now flickering backs.

Since I only work in one project, it unfortunately has only occurred in that project. It probably occurs one in fifteen times so it’s hard to trace. Normally I work in XCode and recompile by stopping the project, and restarting it from XCode any time I’m adding a blueprint accessible Event or UPROPERTY. This ends up being a lot of restarts of the editor. The frequency seems random but when working full days, it will happen at least once, and requires stopping the editor and restarting because it’s not usable while the condition exists. That always fixes it. The dual monitors are ViewSonics, one running HDMI and the other SVGA through a Mac mini adaptor cable. I normally load the editor on the HDMI screen and that is where I’ve seen this. It doesn’t help to slide the editor over to the other monitor at the time it occurs.

My son, the modeler, also uses a Late 2013 Pro like mine. On his, it happens less frequently, but he will leave the project open continuously until it crashes (for unrelated reasons), since he doesn’t do C++ compiles. He tells me it has happened only 4 times in the last two weeks on his system. He has only one monitor but it is not an Apple monitor. He runs DVI. He also has dual 700 video cards. He went from 4.14 to 4.18 directly, and the problem had not occurred for him until the upgrade.

We will be glad to provide any information we can if you tell us what you need. Thanks.

One additional thing I noticed this week, but forgot to mention, When the flickering occurs, other applications in the background will show through in spots of the editor, including other editor windows (e.g., output and message logs which I leave unpinned to the main window).

I just had the problem and stopped to look at it for moment. I was incorrect about one thing. If I move the editor window to my second screen, the problem disappears. Then I can move it back to my primary screen and it continues to work normally.

The second thing I did was go to my hot corner to display all windows (used to be called expose, don’t know what they call it now), the image of the editor screen continued to flicker even in the smaller reduced size window shown, while no other windows flickered.

Still happening for us too at 4.18.3. I’ve found it happens most often when I start the editor from XCode. My son has it happen less but always starts from the uproject file. My workaround is to move the window to a second monitor and back, it always gets rid of it. I found this happens occasionally on just the log window (which I keep detached from main editor window).

Without a second monitor, you might try moving it to a second virtual desktop, then moving it back. I’ll try that today when it flickers and see if that fixes it like moving to a second monitor does.

I am experiencing the same flickering on a macbook pro late 2017 on my built-in monitor (no external monitor) in ue4.18.3

I cannot consistently reproduce it, but it often happens after resizing the editor window while CPU use is high.

This problem has not reoccurred in 4.19. I assume that also is because other things have improved on the user interface when using two monitors on a Mac. The solution is moving to 4.19.

@ C I’m Having Exactly this Behaviour since 2 months, did a Full Rename of the project before. I manage to crash it Twice Wanting to select a attribute on the flickering list. I didn’t have Debugging on so can provide more information except the callstack:

UE4Editor_Core!FDebug::OptionallyLogFormattedEnsureMessageReturningFalseImpl() [d:\build\++ue4\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:433]
UE4Editor_Engine!UEdGraphPin::SanitizePinsPostUndoRedo() [d:\build\++ue4\sync\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:2105]
UE4Editor_UnrealEd!UEditorEngine::BroadcastPostUndoRedo() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\editorserver.cpp:5111]
UE4Editor_UnrealEd!UEditorEngine::HandleTransactorRedoUndo() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\editorserver.cpp:1195]

i managed to get a capture from the flicker activating e.g. ShareX Video Capture gets rid of the flicker until deactivation then it starts again.

https://www.youtube.com/watch?v=VLEP_B9q02Y

I’ve seen flickering occur when using a high resolution but changing it down to a lower resolution mitigates the issue.

3840x2160 == flickering.
1920x1080 == no flickering.

Managed to fix this by deleting the config folder under \saved\config, restoring the default editor state.

Managed to fix this by deleting the config folder under \saved\config, restoring the default editor state.