When you use the CreateWindow command, the last parameter is used to specify it's style
1 - The window has a title bar
2 - The window is resizable
4 - The window has a menu
8 - The window has a status bar
16 - The window is a 'tool' window
32 - The window shape is in 'client coordinates'
e.g. 1 + 2 + 4 would give you a resizable window with a titlebar and menu. Style 16 is what you want, it makes the window borderless.
1 - The window has a title bar
2 - The window is resizable
4 - The window has a menu
8 - The window has a status bar
16 - The window is a 'tool' window
32 - The window shape is in 'client coordinates'
e.g. 1 + 2 + 4 would give you a resizable window with a titlebar and menu. Style 16 is what you want, it makes the window borderless.
Win = CreateWindow("Title", 0, 0, ClientWidth(Desktop()), ClientHeight(Desktop()), 0, 16)should do what you need