Bugzilla

Documenting my findings for future archaeologists:

It appears that in macOS 11, `MOZTitlebarAccessoryView`'s `viewWillMoveToWindow:` is called both when transitioning to full screen, and when transitioning out of full screen. In the case of transitioning into full screen, the window passed to `viewWillMoveToWindow:` has `titlebarAppearsTransparent=false`, meaning that the condition added to this function in bug 1906034 caused the title bar separator to always be enabled when in full screen on macOS 11. Unfortunately the original comment in this function misled me a bit here originally, but we will fix it :)

In later releases, `viewWillMoveToWindow:` seems to be called when transitioning out of from full screen, but not when transitioning to full screen. This is why disabling the title bar separator in `windowDidEnterFullScreen:` is also needed to fix the issue for later macOS releases (which was reproduce-able with the browser title bar enabled).

Documenting my findings for future archaeologists:

It appears that in macOS 11, `MOZTitlebarAccessoryView`'s `viewWillMoveToWindow:` is called both when transitioning to full screen, and when transitioning out of full screen. In the case of transitioning into full screen, the window passed to `viewWillMoveToWindow:` has `titlebarAppearsTransparent=false`, meaning that the condition added to this function in bug 1906034 caused the title bar separator to always be enabled when in full screen on macOS 11. Unfortunately the original comment in this function misled me a bit here originally, but we will fix it :)

In later releases, `viewWillMoveToWindow:` seems to be called when transitioning out of from full screen, but not when transitioning to full screen. This is why disabling the title bar separator in `windowDidEnterFullScreen:` is also needed to fix the issue for later macOS releases (which was reproduce-able with the browser title bar enabled). Note that using `windowDidEnterFullScreen:` alone is not sufficient to solve the issue on macOS 11, which is why we have both.

Documenting my findings for future archaeologists:

It appears that in macOS 11, `MOZTitlebarAccessoryView`'s `viewWillMoveToWindow:` is called both when transitioning to full screen, and when transitioning out of full screen. In the case of transitioning into full screen, the window passed to `viewWillMoveToWindow:` has `titlebarAppearsTransparent=false`, meaning that the condition added to this function in bug 1906034 caused the title bar separator to always be enabled when in full screen on macOS 11. This indicates that the original assumption that this issue is related to titlebarAppearsTransparent is inaccurate. Unfortunately the original comment in this function misled me a bit here originally, but we will fix it :)

In later releases, `viewWillMoveToWindow:` seems to be called when transitioning out of from full screen, but not when transitioning to full screen. This is why disabling the title bar separator in `windowDidEnterFullScreen:` is also needed to fix the issue for later macOS releases (which was reproduce-able with the browser title bar enabled). Note that using `windowDidEnterFullScreen:` alone is not sufficient to solve the issue on macOS 11, which is why we have both.