macOS has many tools and controls which we rarely use. Although some are arcane and perhaps of limited value, those controlling zooming and other actions on windows are well worth knowing, as they can save you time and effort. This brief article describes those that I know of; I welcome any additional window actions which I have inadvertently omitted.

These apply mainly to ‘well-behaved’ apps which leave macOS to manage their windows. They may not work with those apps which use their own custom windows, though.

Active control areas in addition to the ‘traffic light’ controls are shown above. The red lines mark the edges, the blue are corners (one feature which is actually clearer with Big Sur’s rounded corners), and the area tinted green is the combined title and tool bar seen in the Finder and some apps.

Traffic light controls at the left of the title bar:

• Red – close window; Option- to close all windows in that app;
• Yellow – minimise window to Dock; Option- to minimise all windows in that app;
• Green – zoom window to full-screen mode; Option- to zoom window fully without entering full-screen mode.

Hover the pointer over the green control to display its menu, which also offers full-screen, and tile windows to right or left.

Drag resizing:

• from an edge – resize by that edge (1D); Option- to resize in both directions;
• from a corner – resize by that corner (2D); Option- to resize in all 4 directions;
• Shift-drag from an edge – resize keeping window aspect ratio constant and opposite edge static (2D).

The effect of drag resizing with the Option key held is to resize about the centre of the window.

Double-clicking:

• at an edge – zoom to full along that edge, 1D; Option- zoom to full along both directions;
• at a corner – zoom to full by that corner, 2D; Option- to zoom fully without entering full-screen mode;
• in a window with a combined title and tool bar – zoom to full vertically in both directions and shrink to a minimum in the horizontal direction;
• in an app window title bar – zoom window fully without entering full-screen mode; this is controlled in the Dock & Menu Bar pane, and can be changed to minimise if you prefer.

Of all these actions, those involving double-clicking in the title or tool bar are least consistent, and vary between different apps. This has been complicated by changes introduced in Big Sur.

Some of these actions are reversible in the sense that, once you’ve zoomed a window out, you can repeat the same action to zoom it back in to its former size.

Another generally useful trick is to Command-drag a background window, which lets you move it without bringing it to the front.

I hope you find those useful.

Thanks to Simon and Javier for their additions.