In tools -> options -> languages ... c/c++ -> C/C++ Preprocessing
you need to add SFR_16BIT to the list of #defines and specify the expansion.
<quote from the options dialog>
For performance considerations, Context Tagging® does not do full preprocessing, so macros thatinterfere with normal C++ syntax can cause the parser to miss symbols. To prevent this, use this page to add the necessary preprocessing macros. Arguments are allowed, for example: mymacro(a,b,c) You can add large numbers of #defines directly to the usercpp.h file located in the user config directory.
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