The Multitasking Optimization Vector
If you are cross-referencing a PDF document while simultaneously writing an email on a Mac, manually dragging and resizing the two windows so they sit side-by-side without overlapping is a frustrating and imprecise exercise. You end up wasting valuable screen real estate with awkward gaps, or the windows slightly clip into each other. You must instruct the macOS window manager to mathematically divide the screen perfectly in half and lock the applications into place.
How to Use Split View
macOS features a native, hardware-accelerated snapping engine that forces two applications to share a dedicated, distraction-free Full Screen workspace.
1. Ensure both applications you want to use are open and currently visible on your screen (they cannot be minimized to the Dock).
2. Move your cursor to the top-left corner of the first application’s window (e.g., Safari).
3. Locate the three coloured traffic light buttons (Red, Yellow, Green).
4. Hover your cursor directly over the Green button. Do not click it; just let the cursor rest on it for one second.
5. A small dropdown menu will appear.
6. Select either Tile Window to Left of Screen or Tile Window to Right of Screen.
7. Safari will instantly snap to fill exactly 50% of your monitor.
8. The remaining half of your screen will display expose-style thumbnails of all your other open applications. Click on the thumbnail of the second app (e.g., Apple Mail).
9. It will instantly snap into the remaining empty space.
You are now in an isolated Split View. To adjust the ratio, click and drag the thick black dividing line in the absolute center of the screen to give one app more space than the other. To exit, press the Escape key or click the Green button on either window again.