Hi Sunil,
Iniside ScreenMaker, the CommandBar is treated as a Menu control. This means that it could only be located at the bottom of the Screen (similar to a Menu inside a Form, which is always located at the top of the Screen). The workaround will be to add the CommanBar inside a Panel, and just re-locate the Panel.
PD. We might need to hide some of the layout properties to avoid these confusions.
BR/Carlos