Bug 43228 Encoding Support for Java editor broken
I20030916 This has been broken with the introduction of ExtendedTextEditor.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
if (viewer instanceof ITextViewerExtension3) {
					ITextViewerExtension3 extension= (ITextViewerExtension3) viewer;
					offset= extension.modelOffset2WidgetOffset(offset);
				} else {
					offset -= viewer.getVisibleRegion().getOffset();
				}
				
				StyledText text= viewer.getTextWidget();
				try {
					text.redrawRange(offset, length, true);
				} catch (IllegalArgumentException x) {
					JavaPlugin.log(x);
				}
			}
			
			fActiveRegion= null;
		}
				
		private IRegion selectWord(IDocument document, int anchor) {
		
			try {		
				int offset= anchor;
				char c;
	
				while (offset >= 0) {
					c= document.getChar(offset);
					if (!Character.isJavaIdentifierPart(c))
						break;
					--offset;
				}