Custom regions

The built-in commands cover halves, quarters, maximize and center. A custom region is anything else: left two thirds, a centred column, the top strip of an ultrawide.

Creating one

Two ways in:

• From the overlay. Make a selection and press ⌘S while the grid is still up: either holding the mouse button down rather than releasing it, or after selecting with the arrow keys. Releasing a drag places the window and dismisses the overlay, which leaves nothing to press ⌘S on. The picker opens already filled in, with a suggested name.
• From Settings. Open Settings ▸ Shortcuts and choose Add region…, then draw on the grid in the sheet. Arrow keys and ⇧-arrows work here too.

Then name it, click the shortcut field, press the combination you want, and click Add.

A region remembers its own proportions

So you can set the grid to 6 columns to draw a precise third, set it back to 4, and the region still gives you a third.

Editing and deleting

Select a region in Settings ▸ Shortcuts to rename it, redraw it, or change its shortcut. Editing keeps the same region, so its shortcut survives.

Deleting a region also clears its shortcut, and offers an Undo.

Reset Shortcuts puts the built-in commands back to their defaults. Your regions survive it; their shortcuts do not.