How do I troubleshoot this display issue? I wouldn't even know what to search for.

With the window maximised, the Google Chrome menu is blank & higher up than it is supposed to be.

With the window not maximised, the menu displays correctly.

Somebody else had a similar issue. Maximised, all the tabs & the book marks bar had a gigantic white strip displayed instead. Restore the window & you could see all tabs & the bookmarks bar.

Clicking the white area results in no action performed. That means if I tried to click a certain area because I knew what button / tab was supposed to be in that position, nothing happened.