The documentation (Book 2 pdf) states that:
Movable Modal dialog
This type of window stays in front of the applications other open windows until it is closed. Use a Movable Modal window when you need to briefly communicate with the user without allowing the user to have access to the rest of the application. Because the window is movable, the user will be able to drag the window to another location in case they need to see information in other windows.
But it is plain wrong using Xojo 2015r1 / Yosemite 10.10.3PB.
Am I right ?