Bug 139110 GUI enhancement to support create subquery more conveniently.
Description: GUI enhancement to support create subquery more conveniently. Steps to reproduce: Subquery means insert table/list inside another table/list item, and the inner table/list item doesn't has its own dataset binding. In latest build, if you want to creat a subquery structure, you have to use dataSetRow as binding expression for data items in inner table/list item. For example: 1. Insert a list, generate column data binding for it. 2. Add a group for the list. 3. Insert table to list group header which is used to display data rows in list group. Dont' bind table to dataset. 4. Insert a data to table detail row. 5. New a binding column for data, click to Open Expression Builder. The issue is that only "Availabel column bindings" is listed in Category but no "Available Data Sets". So I have to type dataSetRow[".."] by myself to generate correct subquery. For users, maybe they will mistakenly use "Available column bindings" which will generate expression like row._outer[".."] and get wrong result. So it is recommended to add "Available Data Sets" in Expression Builder for such case.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
{
			return -1;
		}
		return ( ( rgb.red & 0xff ) << 16 )
				| ( ( rgb.green & 0xff ) << 8 )
				| ( rgb.blue & 0xff );
	}
	/**
	 * Gets the list of data sets which can be used for the specified element
	 * 
	 * @param handle
	 *            the handle of the element
	 * @return Returns the list of data sets which can be used for this element
	 */
	public static List getDataSetList( DesignElementHandle handle )
	{
		List dataSetList = new ArrayList( );
		if ( handle instanceof ReportElementHandle )
		{
			if ( handle instanceof ReportItemHandle )
			{
				DesignElementHandle dataSet = ( (ReportItemHandle) handle ).getDataSet( );
				if ( dataSet != null && !dataSetList.contains( dataSet ) )
				{
					dataSetList.add( dataSet );
				}
			}
			for ( Iterator itor = getDataSetList( handle.getContainer( ) ).iterator( ); itor.hasNext( ); )
			{
				DesignElementHandle dataSet = (DesignElementHandle) itor.next( );