Mouse input is offset in UMG/Slate when the resolution/ViewportSize is changed at run-time (Standalone Game)

Yikes…
Once you get deep enough inside the engine code you discover that many things is a big spaghetti mess. But at least the artists are happy, no? ^^

if Epic wants to fix the underlying bug

This is the problem, isn’t it? Apparently SlateApplication has a lot of bugs (I have heard), and there are other input-related things with how Slate works with GameViewportClient. I’m beginning to understand why big game companies compile Unreal themselves.

Also, if I was in Epic’s shoes - I would probably be really afraid/careful in starting to mess with these things. I’m not confident these things are going to get fixed