I’m developing a text editor that provides a line number view. This view is placed next to the NSScrollView that contains the main text view, rather than inside the scroll view. The line number view updates its drawing in sync with the NSScrollView’s scrolling and text editing in the NSTextView, so it can display the correct line numbers.
This approach worked fine through macOS 15, but on macOS 26 with Liquid Glass, the line numbers end up being drawn without the expected blur/soft edge effect under the window toolbar area.
In AppKit, some view controllers provide APIs to switch edge effects between soft/hard, but I can’t find any API to control this for the window toolbar region. I considered simply not drawing the numbers outside the content area, but if possible I’d like to apply the Tahoe-style soft edge effect instead.
Does anyone have ideas? Is this currently impossible, meaning the only option is to file a feedback/API request? Also, for various reasons, the traditional approach of implementing line numbers by subclassing NSRulerView is difficult for my app.