jPanel1.setParent(jPanel2) will reparent jPanel1 (and similarly any Java component/container) inside jPanel2 (any Java container).
While this might work, it seems to me to be an overly-complex solution. A much simpler one is to set your jScrollPanel’s MouseWheelMovedCallback callback as explained here: http://undocumentedmatlab.com/articles/uicontrol-callbacks

Thanks for a great function! I was trying to put the main panel of my figure into a scrollable panel with the goal of zooming into the panel using shift+scroll and scrolling up and down using normal scroll. I realised quickly however, that the zoom function I added to the WindowScrollWheelFcn property of my figure does not execute on scrolling because the scrolling is captured by the scroll panel.

I’m not familiar enough with java to find out how to capture the scroll events and “re-route” them to my figure if the shift button is down, but I thought of an easier solution, i.e to detach the main panel from the scroll panel whenever I press the shift button and reattach it when I release the shift button. However, I got stuck here too, as I have no idea what to reparent the “jParent” to in what would be the reverse of this:

jPanel = hPanel.JavaFrame.getGUIDEView;
jParent = jPanel.getParent;
jScrollPanel = javaObjectEDT(javax.swing.JScrollPane(jParent));

I guess what I am trying to write is a detachScrollPanel function (similar to the decorateFig/undecorateFig functions). Would appreciate any help!