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
IElementDefn defn )
	{
		assert defn != null;
		boolean retValue = canContainInRom( slotId, defn );
		if ( !retValue )
			return false;
		
		
		if ( isRootIncludedByModule( ) )
			return false;
		if ( !canContainTemplateElement( module, slotId, defn ) )
			return false;
		
		
		if ( isVirtualElement( ) || getExtendsName( ) != null )
			return false;
		
		DesignElement tmpContainer = this;
		while ( tmpContainer != null )
		{
			if ( tmpContainer instanceof ListingElement
					|| tmpContainer instanceof MasterPage )
			{
				List errors = tmpContainer.checkContent( module, this, slotId,
						defn );
				return errors.isEmpty( );
			}
			tmpContainer = tmpContainer.getContainer( );
		}
		return retValue;