SVG: debugging svg export

Hi,

I'm currently debugging SVGFilter::implExportPages() especially around 
line 1336

                    // In case we are dealing with a master page we need to to group all its shapes

                    // into a group element, this group will make up the so named "background 
objects"

                    if( bMaster )

                    {

                        // background objects id = "bo-" + page id

                        OUString sBackgroundObjectsId = B2UCONST( "bo-" );

                        sBackgroundObjectsId += sPageId;

                        mpSVGExport->AddAttribute( XML_NAMESPACE_NONE, "id", sBackgroundObjectsId );

                        if( i == nVisiblePage&&  mVisiblePagePropSet.bAreBackgroundObjectsVisible )

                            aAttrVisibilityValue = B2UCONST( "visible" );

                        else

                            aAttrVisibilityValue = B2UCONST( "hidden" );

                        mpSVGExport->AddAttribute( XML_NAMESPACE_NONE, "visibility", 
aAttrVisibilityValue );

                        mpSVGExport->AddAttribute( XML_NAMESPACE_NONE, "class",  B2UCONST( 
"BackgroundObjects" ) );

                        // insert the<g>  open tag related to the Background Objects

 **                     SvXMLElementExport aExp2( *mpSVGExport, XML_NAMESPACE_NONE, "g", sal_True, 
sal_True );

                        // append all shapes that make up the Master Slide

                        bRet = implExportShapes( xShapes ) || bRet;

                    }   // append the</g>  closing tag related to the Background Objects


The tag opened in the line marked with ** is never closed. (It should be 
closed by the destructor.) I've tested the export with a drawing 
containing a single letter 'a' and in that case there are no background 
objects. So maybe testing if xShapes has no shapes could avoid exporting 
an empty block? But how would I test if xShapes has any shapes?

Any hint concerning the never called destructor for aExp2 and retrieving 
information from xShapes is welcome.

Christina