Yes, 2.6.0 fixes this bug:
<
https://jogamp.org/deployment/jogamp-next/javadoc/jogl/javadoc/interfacecom_1_1jogamp_1_1opengl_1_1fixedfunc_1_1GLPointerFunc.html#a6515b3ec367831131ff9c77a3cdc7db4>
Meaning glEnableClientState is a fixed function pipeline and not available in GL3-core (GL3)
hence should not be a duplicate inside GL3GL3.
<
https://jogamp.org/deployment/jogamp-next/javadoc/jogl/javadoc/interfacecom_1_1jogamp_1_1opengl_1_1GL2ES3.html>
For 2.6.0 I have spend some good time adding new profiles (ES 3.2) and extensions,
as well as removing duplicated.
So far I am glad that this change has worked out and didn't cause big troubles.
Solution: Use a GL2 or otherwise fixed function GL object implementing GLPointerFunc
and recompile.
Hope this is acceptable.
@Julien: Maybe a new Ardor3D build is warranted?