From Xojo Documentation
Displays the window within the parentWindow. If the window is a Document window, it is displayed in a modeless state and is equivalent to Show.
Used to display Sheet and Drawer windows on macOS within a specific parent. For sheet windows, it is displayed in a modal state. For a Drawer window they are displayed in a modeless state. The optional facing parameter pertains to Drawer windows and indicates which side the drawer pops out of the side shown in the table below:
|-1||Default (determined by the system -- usually left),|
|3||Left (same ordering as tab panels).|
If you omit facing, the default value will be used.