On 3 Oct 2017, at 0:37, Nigel Chapman wrote:

In recent versions of various Apple programs, including Safari, Preview and iBooks, when you go into full screen mode, the sidebar hides itself until you roll over the edge of the screen with the cursor. I sometimes use Textmate on a laptop with a relatively small screen, and increasingly use it in split-view mode on my iMac, and in those cases things get a bit cramped, so it would be nice if the file browser in Textmate behaved in the same way.

I had thought that I remembered when the Apple programs started doing this that I read about it being trivial to implement […]

The functionality for this is NSSplitViewController which has support for “sidebar behavior” in 10.11.

I do plan to adopt the controller, but ironically I am having some issues with its sidebar behavior because it requires a blurred background, and I just found a solution to the file browser color I am happy with, which does not require a blurred background, plus the controller’s setup of a blurred background causes rendering issues, but presumably that is fixable.