xcode - TabViewController : centering the children views & setting the background

Question

I have a SplitviewController, with a tabViewController embed in the right part of it. the 3 buttons inside the left apnea are used to display 3 different windows.

First issue: there's some kind of grey background appearing for Windows 2 and 3 but not for the first, I can't figure out how to get rid of it

Window 1

Window 2

Designer

Second issue : I don't know how to center the view of my windows inside the TabView (on the picture above you can see that the label isn't displayed at the center of the right panel despite being centered in the designer).

Edit : Second issue solved. I still don't figure out how to remove the background.

Answer 1

等待大神答复