Bug 336684 [JFace] NPE in Tray Dialog
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/TrayDialog.java
return link;
	}	
	
	/*
	 * Returns whether or not the given layout can support the addition of a tray.
	 */
	private boolean isCompatibleLayout(Layout layout) {
		if (layout != null && layout instanceof GridLayout) {
			GridLayout grid = (GridLayout)layout;
			return !grid.makeColumnsEqualWidth && (grid.horizontalSpacing == 0) &&
					(grid.marginWidth == 0) && (grid.marginHeight == 0) &&
					(grid.numColumns == 5);
		}
		return false;
	}
	/**
	 * Returns whether or not context help is available for this dialog. This
	 * can affect whether or not the dialog will display additional help
	 * mechanisms such as a help control in the button bar.
	 * 
	 * @return whether or not context help is available for this dialog
	 */
	public boolean isHelpAvailable() {
		return helpAvailable;
	}
	
	/**
	 * The tray dialog's default layout is a modified version of the default
	 * <code>Window</code> layout that can accomodate a tray, however it still
	 * conforms to the description of the <code>Window</code> default layout.