Bug 220767 [Dialogs] PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL
3.3.x and 3.4 M5. The SWT.TOOL flag should be used to create hover style shells, hence the PopupDialog's HOVER_SHELLSTYLE should use SWT.TOOL.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/PopupDialog.java
* @return the foreground color to be used. Should not be <code>null</code>.
	 * 
	 * @since 3.4
	 * 
	 * @see #getForegroundColorExclusions()
	 */
	protected Color getForeground() {
		return getDefaultForeground();
	}
	/**
	 * Get the background color that should be used for this popup. Subclasses
	 * may override.
	 * 
	 * @return the background color to be used. Should not be <code>null</code>.
	 * 
	 * @since 3.4
	 * 
	 * @see #getBackgroundColorExclusions()
	 */
	protected Color getBackground() {
		return getDefaultBackground();
	}
	/**
	 * Return the default foreground color used for popup dialogs.
	 * 
	 * @return the default foreground color.
	 */
	private Color getDefaultForeground() {
		return getShell().getDisplay()
				.getSystemColor(SWT.COLOR_INFO_FOREGROUND);