function colorDrag(element, dragX, dragY, event)
    {
        if (event.shiftKey) {
            if (Math.abs(dragX - initialHelperOffset.x) >= Math.abs(dragY - initialHelperOffset.y))
                dragY = initialHelperOffset.y;
            else
                dragX = initialHelperOffset.x;
        }

        this._hsv[1] = dragX / this.dragWidth;
        this._hsv[2] = (this.dragHeight - dragY) / this.dragHeight;

        this._onchange();
    }
@param {!Element} element
@param {number} dragX
@param {number} dragY
@param {!MouseEvent} event
@this {WebInspector.Spectrum}