Open Radar

 
Summary:
For various reasons I'll explain below when I switch from fullscreen and back I end up setting the alphaValue for close, miniaturize and zoom window buttons to 0.0 and then back to 1.0 after. This causes the buttons to look permanently disabled. It also seems to break the mouse-over code too.
This is code that isn't yet used in production but I'm working on using it for the next version of Tweetbot Mac (for fullscreen/splitscreen support).

Steps to Reproduce:
1. Fire up included example app.
2. Click fullscreen button
3. Move mouse to top of window so you can see window titlebar.
4. Click exit fullscreen button
5. Note that window buttons are now all disabled.
6. If you comment out the code that that sets their alpha to 0.0 and then 1.0 then everything works as expected. The reason I do this is because the buttons jump when I bring back the (empty) toolbar in order to vertically center the window buttons.

Expected Results:
I'd expect that the window buttons wouldn't break just because I made them invisible and then brought them back. This used to work in 10.10/10.9. I played around with fading the window buttons in and out in Calcbot for Mac but that code never shipped.

Actual Results:
Window buttons (close, miniaturize, zoom/fullscreen) all no longer like having their alpha value set to 0.0 and then back to 1.0.

Version:
10.11.1 Beta (15B30a) and also tested on 10.11 too.

Notes:
The reason I hide and show the toolbar is because in Tweetbot that vertically centers the window buttons. I never put anything in the toolbar. It is only there to center the window buttons. I draw my own titlebar that is taller than the standard titlebar.
The reason I hide the toolbar when I go into fullscreen is because otherwise the floating toolbar window is too tall. It just needs to be tall enough to show the window buttons so the user can close the window or exit fullscreen.

Configuration:
MacBook Pro 15 Retina (2012) and Mac Pro 2008 (running 10.11.1 beta)

Attachments:
'FullScreenWindowTesting.zip' was successfully uploaded.