When you have an app’s windows sized just as you want them in macOS, it can be a shock when a slight movement in Sequoia suddenly causes the window to balloon to fill the screen. What changed? Apple added new options in System Settings > Desktop & Dock in the Windows section that can help you manage windows, but there’s one you may want to disable.
Apple beefed up the Windows section between macOS 14 Sonoma and 15 Sequoia. In 13 Ventura and 14 Sonoma, you had the first three options: “Prefer tabs when opening documents,” “Ask to keep changes when closing documents,” and “Close windows when quitting an application.” Sequoia added a whopping four new ones.
Read more at Macworld.com