Mouse sensitiviy issues and crashes while painting on macOS

This is probably a duplicate of Mouse acceleration while painting - Programming & Scripting - Unreal Engine Forums, but since that one was not posted as a bug report, I figured it would be best to report it again, here.

On the latest macOS 10.12, it is impossible to use the paint or sculpting tools properly. Moving the mouse works just fine, but as soon as a mouse button is clicked (and thus, painting is started), the mouse becomes… unpredictable. It feels like the sensitivity randomly jumps up and down.

It is incredibly hard to describe verbally, so I recorded a screen cast and attached it (mp4 in zip). Here, I’m first moving my mouse in a circular pattern, without clicking. Then, I click and hold the left mouse button, while doing exact the same hardware inputs. It is clear that mouse movement not only gets slowed down (which could be okay), but also, the radius increases and I am no longer drawing a circle, but a … random egg shape. At second 38, you can see the mouse drift off in the distance, and there is no way to counter that drift.

Sometimes, the mouse randomly jumps off-screen. Sometimes, while drawing, the editor crashes. I submitted crash reports for them, but just for reference, here is a stack.

I am aware that this sounds like I am drunk while drawing (I’m not!), but believe me, this is an issue, that, sadly, renders the editor almost useless on macOS.

Edit: My stack looks very similar to the one in UE-49008, and apparently, a fix is already landed for 4.18? Is there any way for me to test that, and maybe confirm that this issue is resolved?

Since it’s weekend and I had some time, I built UE4 off the current master myself. The issue seems to be resolved, so apparently, it’s fixed with 4.18! That’s totally cool by me then, but I’m not accepting my answer just yet, maybe someone who knows a bit more context can jump in to confirm that I’m not seeing ghosts.

Hi theschub,

Thanks for letting us know about this. I was able to see what you described happen in 4.17.1, though in my case it seemed a bit more extreme than what you showed in your video, and it only happened for me the very first time I tried to paint in the project. Subsequent attempts appeared to work fine. I also saw that it appears to have been corrected in the Master branch, since the erratic movement did not occur there.

Hi ,

thank you very much for confirming! So we can all be happy now. :slight_smile: