fullscreen multiwindow OS X bug?

[René J.V. Bertin]

Hi,

I ran into what looks to be a bug in Apple's fullscreen algorithms. On 10.9.5 with screens DO NOT have separate spaces:

1) open a Terminal.app window, write down the shell's PID
2) make it fullscreen using the titlebar button
3) open a new window using Command-N
4) exit from fullscreen mode

You could expect the window created in step 3) to remain a normal window but instead it is made fullscreen too. What's more, it somehow replaces the original fullscreen window which is MIA after step 4). MIA but not closed: it still shows up in the windows menu, and the shell (with PID recorded in step 1)) is still running.

Same happens with a Qt-based console emulator so this is not a bug in Terminal.app .

Is this a known bug (google hasn't been my friend yet finding that answer)?

If not, I'd love to know in what other Mac OS versions this bug can be reproduced and if it depends on the screensHaveSeparateSpaces setting. I'll probably have to upgrade to 10.11 or 10.12 sometime soonish but if anyone is willing to run the few simple steps above I'd really appreciate it.

Thanks,
René