Not all UIs seem to complete drawing in Linux

I’m working on Unreal engine in a Linux environment, and I’m noticing the UI components don’t populate the Blueprint->New Class Blueprint Dialog when launched. I have to actually force the interface to update by, expanding both the Common Classes, and All Classes SExpandableAreas, and then click the select button with nothing selected. This will bring up a new dialog, saying I must select something. This will force the UI to draw for one cycle, and only draw a single common class (Actor), and also, a single All Classes item tree (Object->Actor). If I do this once more, then the full menu is drawn displaying everything you would expect to see. This doesn’t seem to be the only menu that has this issue, the other one I have noticed (which I have not foud a way to force an update) is the FBX Import Options-> Choose Skeleton → Skeleton menu (the menu that is supposed to display skeleton assets in your scene, SFbxOptionWindow::MakeSkeletonPickerMenu). I’m trying to figure out how to force an update, or where to find the code that the UI is using to draw, so I can force updates for now. If anyone has a simple work around for now, that would be great.

There are plenty of problems with UI on Linux, it’s pretty much ongoing work - that said, we’ll try to keep in mind issues you described. Could you elaborate a bit on the details of your set up (desktop environment, display server, drivers and hardware) and the code base (e.g. you using 4.5 or anything earlier)?

Currently the code base we’re on is between current master and just prior to 4.4 being released (we’re working on getting our branch up to the current master, but have found UI items that work on our branch, that no longer work when moving to the new master). We are on Centos, and have made a few modifications to some UI elements (ie.e file browser filters, and menu dropdowns) to get them to display properly. I’m trying to find the UI event loops, to see I could possibly force an update on these items for now? Where would that be in the code?

Thanks.

oh, also, the nvidia driver we’re using is 331.89, on an nvidia quado 600

I would recommend using 4.5 (even now, but better when it’s released) and cherry-picking changes from the master later on - master will be changing a lot and it will add more churn for you, whereas 4.5 should have pretty good Linux experience.

Event loop is in FPlatformMisc::PumpMessages().

We would be very curious to look at your changes to the UI code! If you don’t want to make a PR on github, feel free to e-mail me the diff.

Thanks very much for the reply. We’ll be working on cherry picking to get updated to 4.5. And we’ll keep you posted on how this works out. Thanks again for the help.

This bug still exists in 4.6 and 4.7. But in 4.6 you can’t force UI to redraw list of actors (in 4.7 described workaround works)

Looks like it’s partially fixed in current source of 4.7 branch. At least “common classes” section is rendered immediately with dialog opening. But “All classes” section is till not shown.