Thank you for your post. Without seeing the specific details you describe on a screenshot, I generally prefer uploading an image to facilitate easier understanding. I can certainly appreciate your perspective. Additionally, providing code is always beneficial, as it allows others to make modifications or offer recommendations.
Other developers will jump in this thread and provide their opinion as well.
For what I believe is when content appears underneath a translucent toolbar in macOS, macOS applies a blur effect to enhance readability. The level of blur and dimming depends on whether the content is scrollable or static.
To make your non-scrolling view behave like the view inside the NSScrollView, you can manually apply a similar visual effect by layering a visual effect view behind your content.
Adjust the visual effect view's properties to match the exact appearance you desire, ensuring it complements your app's design.
Looking forward to see the screenshot if possible.
Albert Pascual
Worldwide Developer Relations.