I'd report it as a bug just in case it's not expected behavior.
With the popover being a relatively new layout object, and given the nature of what a popover is (window inside of a window); it's most likely something that is a result of the window state when a popover is open locking certain UI components as long as it stays open.
My setup is MacOSX 10.11.6, FMA15. I'm not sure if this is a matching scenario, but I just tried to replicate what you describe:
1. opened a file, then opened a second window.
2. put the second window into Table View
3. opened a popover on the first window, put cursor inside a field in the popover
4. shifted focus to the second window—first window remained as I'd left it
5. entered data in a field in Table View window—no change in first window
6. resized a field in Table View window—field resized but popover on first window closed
7. same result if I rearranged a field
I certainly experience no restriction of my ability to manipulate the Table View layout. How is that different from what you were doing when you had this issue?
Thanks, keywords. It is interesting to see you get a different behavior and the difference between us is 10.11 and 10.12. When I try to move fields or resize them in table view, the popover in the other windows does not automatically close in my solution. Interesting. Thanks for your input!
Have you tested this with another file?