This is the official response I received from Leica Camera on the allegations that the new T mirrorless camera was somehow based on the AppCam OS concept:
With the Leica T, Leica Camera AG has launched a system camera featuring a, for cameras, innovative operating concept in conjunction with touchscreen control. The design, development and realisation of this operating concept began in spring 2010 in Leica’s own facilities and led, in March 2011, to the successful recognition of several protective rights applications submitted at this time by Leica Camera AG. These protective rights applications are based exclusively on developments conceived and realised within and by our company.
Any claims, allegations or insinuations that the Leica T operating concept is based on or derived from developments by other parties are totally without foundation.
The operating system developed by AppCam was presented to Leica Camera AG in November 2011, many months after the development of the Leica T-System operating concept and the corresponding protective rights applications from March 2011. One of the characteristic features of AppCam OS is the setting dials immediately adjacent to the application fields. The Leica T operating concept has no setting dials and differs significantly from the AppCam concept in numerous other ways.