Bug 182076 Delete a style from a report item doesn't affect report xml source
Steps to reproduce: 1.Insert a label onto layout; 2.New a style, suppose named it "NewStyle"; 3.Right click the label and on the drop down list, choose Style->Apply Style->NewStyle; 4.Save the report design; 5.Right click the label and on the drop down list, choose Style->Delete Style->NewStyle; 6.Save the report design; Expected result: NewStyle is deleted from report design, and the label doesn't have the style property. Actual result: Switch to report xml source, a error mark indicate that the label still has a style property:<property name="style">NewStyle</property>
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/core/commands/DeleteCommand.java
*/
	protected boolean canDrop( Object source )
	{
		if ( source == null )
		{
			return false;
		}
		if ( source instanceof List )
		{
			return canDrop( ( (List) source ).toArray( ) );
		}
		if ( source instanceof StructuredSelection )
		{
			return canDrop( ( (StructuredSelection) source ).toArray( ) );
		}
		if ( source instanceof Object[] )
		{
			Object[] array = (Object[]) source;
			if ( array.length == 0 )
			{
				return false;
			}
			
			for ( int i = 0; i < array.length; i++ )
			{
				if ( DNDUtil.checkContainerExists( array[i], array ) )
					continue;
				if ( canDrop( array[i] ) )
					return true;
			}