This is in NetBeans 6.5, Java 6.
I have the following hierarchy in the NetBeans GUI Designer:
JFrame
JTabbedPane
JPanel X
<...>
JPanel
JButton
JPanel Y
<...>
JButton
JPanel Y is identical to JPanel X, so I'd like to simply reuse JPanel X in both places, but how do I do this inside the GUI Builder?
I tried copy-pasting JPanel X, but it creates a full "deep" copy (JPanel X1, etc), duplicating everything in JPanel X.
Some googling indicated it might be possible to add it to the Palette, but I haven't found a way to add a simple JPanel to the palette (as opposed to a complete JFrame).
Create a separate JPanel class. Customize JPanel as needed. You can then drag-and-drop the JPanel class onto the Form Designer. This is exactly what I do.
Alternatively, you can click on Use Bean and then type in the name of the class.
Alternatively, you can do an Add from the pallete and it will scan your JAR for any "beans". It should pick up your custom JPanel as well.