Hybrid User Interfaces (HUIs) describe a combination of several devices into one system. Such a combination promises to alleviate the disadvantages of one device by adding features of another. The term HUIs was first coined by Feiner and Shamash [10] in 1991. Since then, many research projects have focused on exploring possible systems within this interface category, showing the importance and interest of this term. However, the broadness of the follow-up research projects can be seen as "wild growth", which caused the term HUI to become unspecific and fragmented - as also the call for submission of this workshop states [14]. Additionally, a set of related terms have been used since then, which partially overlap with HUI, like cross-device interfaces or augmented displays.