xtd - Reference Guide  0.1.0
Modern c++17 framework to create console, gui and unit test applications on Windows, macOS and Linux.

§ top_level() [2/2]

virtual form& xtd::forms::form::top_level ( bool  top_level)

Sets a value indicating whether to display the form as a top-level window.

true to display the form as a top-level window; otherwise, false. The default is true.
A Multiple-document interface (MDI) parent form must be a top-level window. So set to false has no effect.
A top-level form is a window that has no parent form, or whose parent form is the desktop window. Top-level windows are typically used as the main form in an application.