This issue is forked from  issue 847179 . 

While I was investigating that bug, I found that it's possible that we actually set focus on an invisible window. (See comment #6 in  issue 847179 ).


I tried changing Window::CanFocus() by adding a check for visibility after the first check for root winodws, essentially making it look like:

bool Window::CanFocus() const {
  if (IsRootWindow())
    return IsVisible();

  if (!IsVisible())
    return false;

  ....
}

This fixed  issue 847179 , but reading this comment in [1] made me question this solution, so I didn't go forward with this fix.

  // NOTE: as part of focusing the window the ActivationClient may make the
  // window visible (by way of making a hidden ancestor visible). For this
  // reason we can't check visibility here and assume the client is doing it.

[1]: https://chromium.googlesource.com/chromium/src/+/0970add0c5df6be31505bf21f4f4f22992faa0b5/ui/aura/window.cc#653


This bug is here to think about what needs to be done, so that I can close  issue 847179 .