This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
There is a slight delay when clicking between two different UMG buttons on Mac. Tested on OSX 10.10.1. There also appears to be a flicker on the Menu Bar.
1. Open the Content Examples project
2. Open the UMG map
3. Move to 2.1
5. Activate the button
6. Click the Decrease Progress button
7. Click the Decrease Progress button again
8. Click the Increase Progress button
9. Click the Increase Progress button again
There is a slight delay when clicking the second button the first time. Clicking it again proceeds without delay. Clicking the first button repeats the delay. Also note: when the focus is switched to another button, the OS Menu Bar flickers.
Head over to the existingAnswerHub thread and let us know what's up.