Bug 151959 inappropriate screen operation
steps to reproduce: - create a report - add a grid item (3x3) - switch to Outline view - expand the grid item to see its rows and cells - select the grid item, and drag it into any of its own cell expected behavior: - is it an invalid screen operation? if it is, it should be banned actual behavior: - the grid item was disappeared surprisingly
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* Checks whether the root of the current element is included by
	 * report/library.
	 * 
	 * @return <code>true</code> if the root of the current element is
	 *         included by report/library. Otherwise <code>false</code>.
	 */
	private boolean isRootIncludedByModule( )
	{
		DesignElement tmpContainer = getRoot( );
		if ( tmpContainer instanceof Library
				&& ( (Library) tmpContainer ).getHost( ) != null )
		{
			return true;
		}
		return false;
	}
	/**
	 * Determines if the current element can contain an element with the
	 * definition of <code>elementType</code> on context containment.
	 * 
	 * @param module
	 *            the module
	 * @param slotId
	 *            the slot id
	 * @param defn
	 *            the definition of the element
	 * @return <code>true</code> if the slot can contain the an element,
	 *         otherwise <code>false</code>.
	 */
	public final boolean canContain( Module module, int slotId,