jsfiddle/OpenLayers.debug.js
function(feature, pixel) {
                if(feature === control.box) {
                    control.transformFeature({center: control.center});
                }
            }
function(feature, pixel) {
                if(feature === control.box) {
                    control.transformFeature({center: control.center});
                }
            }
function ( feature , pixel ) { if ( feature === control . box ) { control . transformFeature ( { center : control . center } ) ; } }
transform while dragging
transform while dragging