I have a suggestion about the windowed mode. First of all, I wish I can pin windows. What I mean by pinning window is, being on the top layer of all windows. For example, if I pin a window and launch skype (full windowed mode), my pinned window will stay on top of skype instead of having skype covering it.
Second, I would like to see fullscreen adjustments. Before I talk about the new adjustments, I am desperate when will Microsoft will fix the issue where when I exit fullscreen (1920x1080) to desktop (3840x2160), my other opened apps resizes it's window. I̶t̶'̶s̶ ̶f̶r̶u̶s̶t̶r̶a̶t̶i̶n̶g̶! Now, back to the point about the new adjustments, I think it is better to have a fullscreen as a desktop instead of desktop 1 for example. In simple words, the fullscreen should show up as a descrete desktop like in Mac OS.
Finally, remember windowed size would be useful. Bascially you set a size of the window and if you accidently change your window size, you can revert it back to the size you chose. (maybe add a additional button for revert window size)