I'm working on a project and suddenly Xcode (Version 9.1 (9B55)) stopped showing the descriptions of classes, methods etc. in a Quick Help. I can see the same behaviour when I option-click on the classes and methods. Here how it looks, for example, when I tap on a viewDidLoad() method:
However, when I open another project, it works fine. Here is a screenshot from another project, when I tap on a viewDidLoad() method:
So, I think, this isn't an issue related to Xcode itself (or I'm wrong), but maybe I have accidentally broken something in my project. Anyway, I can't figure out what can cause this issue. Do you have any ideas?