Bug 16181 Tab key doesn't work in editor when 'Insert spaces for tabs' enabled
Using integration build 0515, pressing Tab in an editor window doesn't do anything when 'Insert spaces for tabs' is selected. The editor is marked as unsaved, but no spaces appear.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
public boolean isVerticalRulerVisible() {
			return fCachedIsVerticalRulerVisible;
		}
		
		public OverviewRuler getOverviewRuler() {
			return fOverviewRuler;
		}
		
		/*
		 * @see TextViewer#createControl(Composite, int)
		 */
		protected void createControl(Composite parent, int styles) {
			
		}
		
		protected void delayedCreateControl(Composite parent, int styles) {
			
			super.createControl(parent, styles);
			
			Control control= getControl();
			if (control instanceof Composite) {
				Composite composite= (Composite) control;
				composite.setLayout(new AdaptedRulerLayout(GAP_SIZE, this));
				fOverviewRuler.createControl(composite, this);
			}
		}
		
		public void hideOverviewRuler() {
			fIsOverviewRulerVisible= false;