Sometimes when I open a storyboard file, the interface builder stays loading. What's worse, it also MAGICALLY hangs other applications / actions like opening new terminal app window, executing git commands, opening visual studio code editor. I didn't test the other app as I don't want any unexpected outcomes.
The new interface builder has many other bugs as well, but at lease I can still keep working. This hanging issue is really annoying.
I'm using Xcode 8.0 on macOS Sierra.
EDIT
It seems that only the first time I open storyboard will hang Xcode and other applications. It takes minutes before the hanging goes away.
Many applications are affected, including Safari, simulator, some IM applications, and more.
I really don't understand why openning storyboard would hang other applications.