Bug 188027 PasteAction is diabled
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/elements/Theme.java
*            the css to drop
	 * @return the position of the css to drop
	 */
	public int dropCss( CssStyleSheet css )
	{
		if ( operation == null )
			return -1;
		return operation.dropCss( css );
	}
	/**
	 * Adds the given css to css list.
	 * 
	 * @param css
	 *            the css to insert
	 */
	public void addCss( CssStyleSheet css )
	{
		if ( operation == null )
			operation = new CssStyleSheetAdapter( );
		operation.addCss( css );
	}
	/**
	 * Insert the given css to the given position
	 * 
	 * @param css
	 * @param index
	 */
	public void insertCss( CssStyleSheet css, int index )
	{
		if ( operation == null )