“Decorations” are the features the window manager adds to a toplevel Window.
This function sets the traditional Motif window manager hints that tell the window manager which decorations you would like your window to
have. Usually you should use
gtk_window_set_decorated on a
GtkWindow instead of using the GDK function directly.
decorations argument is the logical OR of the fields in the WMDecoration
enumeration. If ALL is included in the mask, the other bits indicate
which decorations should be turned off. If ALL is not included, then the
other bits indicate which decorations should be turned on.
Most window managers honor a decorations hint of 0 to disable all decorations, but very few honor all possible combinations of bits.
a toplevel Window
decoration hint mask