Found a workaround for me. If I unplug the external monitor on my MacBook then it works. If I plug it in again then it fails again. Hope that helps.

I think I have found what did I do that triggered this bug. With my external monitor (non-retina) still attached, I went to System Preferences -> Display, dragged the menu back to the MacBook internal display, restarted Xcode, then the problem went away. It seems to be related to external non-retina display chosen as the main monitor.

Widgetsmith is able to show a fuzzy clock (“twenty past four”) with very accurate time. I thought it was possible to have an update every few minutes. I wanted to implement one in a non-English but could not get that kind of update. I wonder what they are doing there.