show in frame:basic-mixin
Shows or hides a window.
The visibility of a window can be changed
by the user clicking the window's close box, for example, and such changes do not go through this method; use on-superwindow-show or on-close to
monitor visibility changes.
( -> void
send a-frame:basic-mixin show on?)
on? : boolean
If show? is #f, the window is hidden. Otherwise, the
window is shown.
If the window is already shown, it is moved front of other top-level windows. If the window is iconized (frames only), it is deiconized.
Calls the super method.
When on? is #t, inserts the frame into the
frame group and when it is #f, removes the frame
from the group.