[FIX] Compiler error when trying to access to protected data.
[FIX] Compiler error when trying to access to protected data.

letaureau/b-tk.core,xyproto/b-tk.core,Biomechanical-ToolKit/BTKCore,xyproto/b-tk.core,letaureau/b-tk.core,xyproto/b-tk.core,letaureau/b-tk.core,letaureau/b-tk.core,xyproto/b-tk.core,letaureau/b-tk.core,letaureau/b-tk.core,Biomechanical-ToolKit/BTKCore,Biomechanical-ToolKit/BTKCore,xyproto/b-tk.core,Biomechanical-ToolKit/BTKCore,Biomechanical-ToolKit/BTKCore,xyproto/b-tk.core,letaureau/b-tk.core,xyproto/b-tk.core,Biomechanical-ToolKit/BTKCore,Biomechanical-ToolKit/BTKCore,Biomechanical-ToolKit/BTKCore,xyproto/b-tk.core,letaureau/b-tk.core