I don't know how to do that but why don't you just use
a JFrame instead.  It will do exactly what you want and
handle the cursor and everything.

Resizing a panel implies other Components will have to change size and
position as well.  Perhaps you might want to rethink and use Frames or
JFrames which can be sized or resized independently, without any
programming effort.

The problem I foresee is every micro change implies a validate/repaint
of the whole app. That might not be smooth or fast enough..

You can check by simulating with timed programmatic micro changes ho
the panels  with validate/repaints, or by seeing the response to
changing the shape of the entire app Frame. You want to run these
experiments on the least skookum computer that will be running your
app.

On Sep 26, 7:08 am, iher...@gmail.com wrote:
...

Put it in an JSplitPane.

As for your latter question 'without mouse', try
JSplitPane + JButton(s) - "Bigger"/"Smaller".

But I say that with little more understanding of
your questions than as expressed by Knute.

Andrew T.