How do I togle/remove the bar at the top of a lister?

How do you move the first one?

There is a small vertical area between the top (where mouse turns into resize cursor) and any elements below, it's active along the whole bar (MS Edge). Also large and small gaps between the top bar elements will allow the window to be moved.
image

image

additionally this app (a media player called potplayer) has no visible title/top bar

unless the mouse hovers over the top line of the window

Does mean that no interactive elements can be in that zone.

Maybe something similar to AutoHotkey.

MyGui := Gui()
MyGui.Opt("-Caption")
MyGui.Add("Text",, "Text")
MyGui.Add("Button",, "OK")
MyGui.OnEvent("Escape", (*)=>ExitApp())
MyGui.Show()

OnMessage(0x201, WM_LBUTTONDOWN)
WM_LBUTTONDOWN(*) {
	PostMessage 0xA1, 2
}