I tried again to reproduce this on a couple macs (one with an Nvidia card and one with an AMD card), but still have not been successful. I will keep poking at it, but this issue appears to be somewhat elusive. I was testing using a Blank Blueprint project. What template had you used for the project you are seeing it in?
Post edited. Added detailed instructions on how to reproduce the bug and a short video clip.
Reproduce:
- Hover the mouse over any button that has a tooltip.
- While the tooltip is displayed switch to another app via Cmd+Tab.
- Cmd+Tab back to UE Editor.
- Now add a new “Blueprint Class”, either by right clicking in the Content Browser or using the “Add New” button in the Content Browser
- The “Pick Parent Class” dialog opens.
- The tooltips in the “Pick Parent Class” dialog should now be hidden behind the dialog.
Here is a short video that shows how to reproduce this bug and how to temporarily work around it:
**Problem:** The tooltips are hidden under the "Pick Parent Class" dialog.Workaround: Cmd-Tab to another app, Cmd-Tab back. Tooltips are now displayed fine.
UE 4.17
System:
iMac (Retina 5K, 27-inch, Late 2015)
macOS Sierra 10.12.6
Screenshots:
The bug:
Workaround, after Cmd-Tab switching to another app and back to UE:
Hi SirToxe,
I tried to reproduce this, but didn’t see the tooltips appearing behind the window. Did you install a binary version of the Engine through the Launcher, or did you build the Engine from source code? Are you using a Blueprint project or a code project?
This is weird. I am trying to reproduce it with a newly loaded project but it doesn’t happen instantly. For a while everything works fine but after some time this bug happens and the tooltip gets hidden behind the window. Once this happens the tooltip is hidden all the time.
While trying to reproduce this it happened to me twice now but I am not sure what exactly triggers this bug to happen. At the moment it seems quite random.
I am using the binary version through the browser and a blueprint project.
Had the bug once again happen to me:
- Clicked on the “Add New” button in the Content Browser
- hovered my mouse over “Blueprint Class” (but didn’t click it yet)
- held Cmd+Alt for the full tooltip
- released Cmd+Alt
- clicked on the “Blueprint Class” menu item
- the “Pick Parent Class” dialog opened
- once I hovered over any of the class buttons the tooltip would again be hidden behind the dialog
But of course once I closed the project and reload it everything worked fine again. Strange.
Alright, got it! Was a bit tricky but is now really easy to reproduce:
- Hover the mouse over any button that has a tooltip.
- While the tooltip is displayed switch to another app via Cmd+Tab.
- Cmd+Tab back to UE Editor.
- Now add a new “Blueprint Class” (either by right clicking in the Content Browser or using the “Add New” button in the Content Browser).
- The tooltips in the “Pick Parent Class” dialog should now be displayed below the dialog.
I have recorded a short video that shows all this. I created a new and empty project for that.
Hello , did you take a look at the video that I just posted a couple of minutes ago? Did you try to reproduce the bug this way? Seems to happen to me every time this way.
As for the template, this can happen in a blank, empty Blueprint project.
I just want to add that the important moment in the example video, that I posted above (UE4 4.17 Tooltip Bug: Tooltips hidden under "Pick Parent Class" dialog on Mac - YouTube), is at 0:35 where I Cmd+Tab to another program while another tooltip is visible. This is the moment when the bug gets triggered.
Hi SirToxe,
Thank you for the additional information. With that I was able to reproduce the issue, and have entered UE-48502 to have this investigated further. I probably would not have thought of having to use Command-Tab initially to go to another app before returning to the Editor.
Great, thank you! 
And yeah, it was quite weird indeed to reproduce or rethink my steps to get this to happen again. 
Hey guys, I just want to point out that the issue UE-48502 can be closed/set to fixed, as this problem has been solved by you guys a while ago.
Hi SirToxe,
Thank you for the update. I ran through the repro case for the ticket in 4.18.3 and 4.19.1 and was not able to see the same behavior any longer. I went ahead and closed that ticket since we cannot reproduce the issue any longer. If you happen to see this behavior again, please let us know.