You can double click the grab handle area of a window (which is less obvious than ever in Tahoe) and it'll fill the window to the display.

Except Safari, which just fills out the window's height vertically. Kinda weird to make an exception like that but I don't hate it, because I generally use Safari for reading, and shrinking the browser's width forces lines of text to not get too long if the website's styling isn't setting that manually.

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empressplay 2 hours ago | parent [-]

You can double click on any part of the top title bar (that doesn't have buttons in it) for example in Calendar you can double click beside the magnifying glass in the top right and it will maximize the window.

	▲	al_borland an hour ago \| parent [-]
		This is running "zoom". When I try it in Finder, it doesn't make the window full screen, it actually made it smaller. When I use the Window menu, Zoom replicates what double-clicking the top title bar does, while Fill maximizes the window. This holds true with the behavior you describe in Safari as well. It just seems like a lot of apps treat Zoom and Fill the same now (I tried Calendar, Notes, TextEdit, and NetNewsWire), which adds to the confusion.