Sun Studio IDE allows users to choose editor:
- Built-in editor(does not support "Split Window" action)
- XEmacs (supports "Split Window" action)
- GVIM (supports "Split Window" action, but only in standalone mode)
So, unfortunately, only one of them allows to split editor window.
Use main XEmacs menu: View -> Split Window
Built-in editor will support "Split Window" in next release.
Thanks,
Nik