* @return a configured source viewer
*/
protected SourceViewer createPatternViewer(Composite parent) {
SourceViewer viewer= new SourceViewer(parent, null, null, false, SWT.V_SCROLL | SWT.H_SCROLL);
SourceViewerConfiguration configuration= new SourceViewerConfiguration();
viewer.configure(configuration);
IDocument document= new Document();
viewer.setDocument(document);
viewer.setEditable(false);
return viewer;
}