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
units = dimension.getUnits( );
		}
		if ( DesignChoiceConstants.UNITS_PX.equals( units ) )
		{
			return measure;
		}
		
		if ( "".equalsIgnoreCase( units ) ) 
		{
			px = measure;
		}
		if ( fontSize == 0 )
		{
			Font defaultFont = JFaceResources.getDefaultFont( );
			FontData[] fontData = defaultFont.getFontData( );
			fontSize = fontData[0].getHeight( );
		}
		if ( DesignChoiceConstants.UNITS_EM.equals( units ) )
		{
			px = DimensionUtil.convertTo( measure * fontSize,
					DesignChoiceConstants.UNITS_PT,
					DesignChoiceConstants.UNITS_IN ).getMeasure( );
		}
		else if ( DesignChoiceConstants.UNITS_EX.equals( units ) )
		{
			px = DimensionUtil.convertTo( measure * fontSize / 3,
					DesignChoiceConstants.UNITS_PT,
					DesignChoiceConstants.UNITS_IN ).getMeasure( );
		}
		else if ( DesignChoiceConstants.UNITS_PERCENTAGE.equals( units ) )