There is nothing special about creating a Frame widget, except you will usually save a reference to the widget so that you can put other things inside it.
# a Frame you'll never see $frame1 = $mw->Frame; $frame1->Button(-text => 'button1')->pack; $frame1->Button(-text => 'button2')->pack; # a more visible Frame $frame2 = $mw->Frame(-borderwidth => 2, -relief => 'groove'); $frame2->Button(-text => 'button1, frame2')->pack; $frame2->Button(-text => 'button2, frame2')->pack; # a Frame in a Frame $frame3 = $frame2->Frame(-borderwidth => 3, -relief => 'raised'); $frame3->Button(-text => 'button1, frame3')->pack; $frame3->pack; # not visible yet $frame2->pack; # still nothing visible... $frame1->pack; # now we can see all the Frames and Buttons
The Frame’s parent can be a MainWindow, a Toplevel, or another Frame widget. After the Frame is created, it can become a parent to other widgets. You must have created the Frame but not necessarily packed it on the screen for it to be the parent of other widgets. Keep in mind that even if you pack other widgets inside your Frame, if you don’t pack the Frame as well, the other widgets won’t show on the screen.
 Technically, any widget can be a parent
of another widget, but life is easier when widgets are children of a
Frame, or else we have to use the
-in option with
pack, confusing everybody. Keep it simple, and
you’ll be much happier.