vl3 is a novel parallel volume rendering framework for visualization of large data sets and has been deployed for visualizing data in several scientific domains including cosmology, astrophysics and bio sciences. The current Python client GUI provides capabilities of streaming the visualization to a remote display and handling basic user interaction. But there is still room for improvement, especially in enhancing the ease of use and the amount of critical data presented. The new Qt-based streaming client GUI provides identical functionality as the legacy Python client. As an extension, it provides a control panel that contains histogram, transfer function editor, real-time rendering parameter saving/loading and other facilities that help the user to easily manipulate the visualization and explore the scientific data.