I have a test project. The main.storyboard has several VC scenes. One scene has 3 NSTableViews in a row and auto layout works perfectly when I run the app. The weird thing is that each time I open the project, the top spacing constraint grows a little (56). I do not modify anything. After several times of re-opening, the value reverts to the standard value.

I am not sure if the problems are only specific to me, but I did not experience similar ones for the past many years. The Quick Help pane always stops displaying help after some time of use (for example, after debugging). I get weird auto layout design time issues in IB (I am sure my constraints are correct). Today I got a weird error when I build one of my test project (something about Array Controller but not in my code). When I close and re-open and build, the problem is gone.

Sorry for not stating my question clear enough. What I want is NSPopoverDelegate so that I know when the popover is closed so that I can perform some work accordingly.

Actually, what I want to do is integrate Firebird database engine which requires icu library. But I had problems installing the official package. Are there any successful stories that I can follow?