I have also this error:
Could not open the editor: Cannot instantiate input element factory com.microfocus.eclipse.ui.context.CopybookFileStoreEditorInputFactory for editor id=com.microfocus.eclipse.editor.cobol.CobolEditor name=MIOPROG.CBL
I have also this error:
Could not open the editor: Cannot instantiate input element factory com.microfocus.eclipse.ui.context.CopybookFileStoreEditorInputFactory for editor id=com.microfocus.eclipse.editor.cobol.CobolEditor name=MIOPROG.CBL