This is also happening for me. Basic functionality broken. Again.

Screen recording of the behaviour.

Since the Update to InDesign 2026 (version 21.0) document windows no longer respect panel/palette windows when not using "Application frame". New documents are created behind all panel/palette windows and need to be rearanged by hand. If the zoom button is used the documents window again expaned to use all the space behind all panel/palette windows.

This does *not* happen in Illustrator or Photoshop or even the previous InDesign 2025 (version 20.5). There a new document windows uses the screen space that is left free from the panel/palette windows. And when you use the zoom button it fills to this same free space.

The new InDesign 2026 update completely ruined the window management on macOS. When clicking the green maximize button, the app now jumps into full-screen mode instead of simply maximizing the window as before. There is no way to disable or revert this behavior.
Whoever decided this clearly doesn’t use InDesign for real professional work. Constantly jumping windows and forced full screen make the app nearly unusable for layout professionals. It breaks focus, interrupts workflow, and wastes valuable production time.
Please bring back the previous window behavior, or at least give users an option to disable this forced full-screen mode. This is not an upgrade, it’s a huge step backward. A professional layout tool should enhance control, not take it away.
Version: InDesign 2026 (macOS)
Category: Performance/Usability
Expected result: Window should resize normally without entering full-screen
Actual result: Green button forces full-screen mode, destroying workspace flexibility

Version: InDesign 21.0, MacOS 15.6.1

Steps: Opening any document or making new document. Application Frame off.

Expected: Document window should expand to the edge of docked pallets but not go underneath them (behavior prior to v21.0)

Actual: Document window always expands to the screen edge underneath any/all open pallets.

Yes application frame doesn't have the issue but I've never been a fan of it. Beta is fine, just the new 2026 version

Just updated to InDesign 2026, and document windows are running behind tool windows (e.g., Swatches, Paragraph, etc.), all the way to the right edge of the screen. In the past, dragging those tool windows all the way to the right edge until I get a blue bar, fixes this issue. Now it does not. And the application does not remember the size I resized the document window to on last save, and it opens it all the way behind the tool windows again. This is super frustrating, as I am often referencing something outside of InDesign on my screen ... and I have to limit the height of my tool windows so I can grab the bottom-right corner of the document window and resize it ... EVERY TIME I OPEN THE DOCUMENT. Please fix this ASAP! Thank you.

In InDesign 2026, the green maximize button in macOS changed from Zoom to Full Screen (new, separate Desktop) when working with the Application Frame turned off. In InDesign 2025, it was great to click the maximize button and the window automatically resizes to fit between the tools and panels. In 2026 it opens in a whole new, separate desktop. Holding Option and clicking doesn't work. Again, I am using InDesign with the Application Frame disabled.

This happens when you have Application Frame disable. Definatly a bug in 2026.

Hi. In ID 2025, I could open a document when I already had a document open, and the new document window would fit the existing window. In 2026, the new document forces the window to expand to fill the screen. This is a problem because I often have a PDF and InDesign file open side by side to do corrections. Now, every time I open a new InDesign file to make edits, it fills the screen over my PDF, and I have to resize the window over and over. It's not a huge ordeal, but it is an inconvenience that has popped up in 2026. It'd be great if it can be returned to the behavior in 2025. Thanks!

Rather than the Maximise button on Mac fitting the document window to the available screen around toolbars and panels, in InDesign 2026 (21.0) it goes to Full Screen Mode and doesn’t not allow you to escape out of it hiding all panels and toolbars.

Only a Force Quite resolves the issue.