Bug 67513 [R21PRES] view tab tool tip inconsistent with 2.1
In 2.1, the tab item tool tip appeared in the stack's title bar, not on the tab item itself. The r21presentation currently puts the tip on the tab item. I'll attach a patch that fixes the problem.
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21BasicStackPresentation.java
* @return
	 */
	protected R21PaneFolder getPaneFolder() {
		return paneFolder;
	}
	/**
	 * Returns true iff the underlying tab folder has been disposed.
	 * 
	 * @return
	 */
	public boolean isDisposed() {
		return paneFolder == null || paneFolder.isDisposed();
	}
	/**
	 * Update the tab folder's colours to match the current theme settings and
	 * active state
	 */
	protected void updateGradient() {
		if (isDisposed())
			return;
		Color fgColor;
		Color[] bgColors;
		int[] bgPercents;
		boolean vertical = false;
		if (isActive()) {
			if (getShellActivated()) {
				fgColor = R21Colors.getSystemColor(SWT.COLOR_TITLE_FOREGROUND);
				bgColors = R21Colors.getActiveViewGradient();
				bgPercents = R21Colors.getActiveViewGradientPercents();
			} else {