The grid overlay

Press ⌃⌥O and a translucent grid appears over every display. It takes about 50 milliseconds, and Orthant never becomes the frontmost app, so the window you were using stays active the whole time.

Placing a window

With the mouse. Press inside the cell where the window should start, drag to the cell where it should end, and release. The highlighted block previews exactly where the window will land.

With the keyboard. Arrow keys move the selection. Hold ⇧ and arrow to extend it across more cells. ↩ places the window.

Esc dismisses the overlay without moving anything.

Saving what you just drew

⌘S places the window and opens a shortcut picker pre-filled with the selection you made. Orthant suggests a name: draw the left two thirds and it offers “Left ⅔”.

It has to be pressed while the overlay is still up, because releasing a drag places the window and dismisses the grid. So either:

• keep the mouse button held down and press ⌘S without releasing, or
• select with the arrow keys (⇧-arrow extends), then press ⌘S instead of ↩.

See custom regions.

Notes

• The grid appears on every display at once, and the window lands on the display you drew on. Drawing on another screen is how you move a window to it.
• The overlay costs nothing while it is hidden: zero CPU, zero wake-ups.
• Esc, ↩ and ⌘S belong to the overlay only while it is on screen. Dismiss it and they go straight back to the app underneath.

Direct shortcuts work the other way round: they keep a window on the display it is already on. See multiple displays.