@Christian_Schmitz
Seems that a solution is described here but I don’t understand the code to put in MouseDown event
i replaced all code above with this code:
Self.NSWindowMBS.isMovableByWindowBackground = True
Var Win As NSWindowMBS = Self.NSWindowMBS
Win.StyleMask = Win.StyleMask Or NSWindowMBS.NSFullSizeContentViewWindowMask
Win.TitlebarAppearsTransparent = True
Win.TitleVisibility = NSWindowMBS.NSWindowTitleHidden
Now, i want to able able to move the window when there is a HtmlView under the title bar.