Tk::tixWm is a Tix's addition to the standard TK wm command.
Converts the toplevel window specified by $widget into a non-toplevel widget. Normally this command is called to convert a Toplevel widget into a Frame widget. The newly-converted frame widget is un-mapped from the screen. To make it appear inside its parent, you must call a geometry manager (e.g. grid or pack) explictly.
Makes the non-toplevel window specified by $widget into a toplevel widget. Normally this command is called to convert a Frame widget into a Toplevel widget, but it can also be used on any non-toplevel widget (e.g, label). The newly-converted toplevel window is in a withdrawn state. To make it appear on the screen, you must call deiconify after calling wmRelease.
Any data associated with $widget via wm methods (icon, protocol, command etc.) are released, and must be re-established if window is later re-captured.