Bug 53888 Mnemonic collision Text Editor -> Quick Diff
20040303 The Make Default and Restore Defaults button have the same mnemonic
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavaEditorPreferencePage.java
fPreviewViewer.invalidateTextPresentation();
	}
	
	/*
	 * @see DialogPage#dispose()
	 */
	public void dispose() {
		
		if (fJavaTextTools != null) {
			fJavaTextTools.dispose();
			fJavaTextTools= null;
		}
		
		if (fOverlayStore != null) {
			fOverlayStore.stop();
			fOverlayStore= null;
		}
		if (fBackgroundColor != null && !fBackgroundColor.isDisposed())
			fBackgroundColor.dispose();
		
		super.dispose();
	}
	
	private Button addCheckBox(Composite parent, String label, String key, int indentation) {		
		Button checkBox= new Button(parent, SWT.CHECK);
		checkBox.setText(label);
		
		GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gd.horizontalIndent= indentation;
		gd.horizontalSpan= 2;