Patch for JXG.Curve.updateRenderer()

curve.js

JXG.Curve.prototype.updateRenderer = function () {
    var wasReal;

    if (this.needsUpdate && this.visProp.visible) {
        wasReal = this.isReal;

        if (this.isReal) {
            this.board.renderer.updateCurve(this);
        }

        this.checkReal();

        if (this.isReal) {
            if (wasReal !== this.isReal) {
                this.board.renderer.show(this);
                if (this.hasLabel && this.label.content.visProp.visible) {
                    this.board.renderer.show(this.label.content);
                }
            }
        } else {
            if (wasReal !== this.isReal) {
                this.board.renderer.hide(this);
                if (this.hasLabel && this.label.visProp.visible) {
                    this.board.renderer.hide(this.label);
                }
            }
        }

        // Update the label if visible.
        if (this.hasLabel && this.label.visProp.visible) {
            this.label.update();
            this.board.renderer.updateText(this.label);
        }
    }
    return this;
};