In the demo windowless I was able to figure out how to remove the frame. Here is the real answer for the issue without having to dig.
In UniServerModule by setting property "MainFormDisplayMode" to
"mfPage" you can remove borders from MainForm.
In this mode instead of a windowed Form, a white blank page is created as
MainForm. This mode only affects the MainForm. All other Forms are
displayed in standard windowed mode.