From Xojo Documentation

Read-Only Property (As DesktopWindow )
DesktopWindowValue = aDesktopContainer.Window

New in 2021r3

Supported for all project types and targets.

Returns a reference to the actual enclosing window.


Exception Reason
NilObjectException Can be raised if the container has not yet been embedded anywhere.


Window walks up the window hierarchy and finds the actual enclosing window regardless of how deeply nested the DesktopUIControl or DesktopContainer hierarchy is.

DesktopControl also has a Window property.