Since 4D on MacOS takes advantage of SDI (Single Document Interface) mode when in design mode, each window is independent from each other. To help increase the speed and organization of your workflow, there is another app known as Spectacle that can help quickly resize windows to half, third, or quarter of the screen and even move windows to another monitor with keyboard shortcuts.

Windows arranged in corners:



Keyboard shortcuts:

Move to the left half: ⌥⌘←
Move to the right half: ⌥⌘→
Move to the top half: ⌥⌘↑
Move to the bottom half: ⌥⌘↓

Move to the upper left: ⌃⌘←
Move to the lower left: ⌃⇧⌘←
Move to the upper right: ⌃⌘→
Move to the lower right: ⌃⇧⌘→

Move to next monitor: ⌃⌥⌘→
Move to previous monitor: ⌃⌥⌘←