template typedef

Last week I knew this code is possible to compile.

typedef CWindowImpl<Hoge> CWindowImpl;

I felt it is a little strange. I could not understand how the compiler interpret these two symbols are different ones. Today, I replaced strtok by boost::tokenizer for better security and readability. Some code fragments I've found via Google used typedef like above. Perhaps it is possible because their namespaces are different, boost and other. I will continue to use this idiom for readability especially code using boost and WTL.