A patch to Raphael to fix handling of empty sets within a set.

raphael_set_getBBox.js

Raphael.st.getBBox = function () {
        var x = [],
            y = [],
            x2 = [],
            y2 = [];
        for (var i = this.items.length; i--;) if (!this.items[i].removed) {
            var box = this.items[i].getBBox();

            // For lack of a better return value, empty sets return 'infinite' bounding boxes
            // But we shouldn't contaminate their parent bounds with this
            // If we come across an empty set, don't include it in the current set's bounds calculation
            if (box.x === Infinity && 
                box.y === Infinity && 
                box.x2 === -Infinity && 
                box.y2 === -Infinity &&
                box.width === -Infinity &&
                box.height === -Infinity) {
              continue;
            }

            x.push(box.x);
            y.push(box.y);
            x2.push(box.x + box.width);
            y2.push(box.y + box.height);
        }
        x = Math.min["apply"](0, x);
        y = Math.min["apply"](0, y);
        x2 = Math.max["apply"](0, x2);
        y2 = Math.max["apply"](0, y2);
        return {
            x: x,
            y: y,
            x2: x2,
            y2: y2,
            width: x2 - x,
            height: y2 - y
        };
    };