We don't have the floating Window on ACAD Mac. You can open two AutoCAD sessions to show two drawings in a screen with either way below:

- right click AutoCAD icon in Dock bar, and select New AutoCAD Session

- right click a drawing tab and select Move to new session

Tip: press tab key to hide the palettes on the left and right side to maximize the canvas size.

Wei Ma
AutoCAD QA Manager