If the `resizeable attribute is 1 (the default), when
the pointer is on the frame a bar and an arrow appear. If the left or middle mouse
button is then pressed and the pointer moved, that edge of the widget is moved, expanding
or contracting the window.
When `resizeable is 1, there are breaks in the frame delineating
resize corners, which can be used to change the size
of the widget in both dimensions simultaneously.
The resizing function can be performed programmatically: see the "Size, position,
etc. on screen or in parent" page.
Pressing the right mouse button with the pointer on the frame displays the window