tab-width 4 in markdown major mode

[Frank Hrebabetzky]

Hi,

I have been accepting over the years that TAB hardly ever means "go to 
the next tabulator stop", but is used for something different in nearly 
each major mode. But I am happy with M-i and tab-width 8, which behave 
the same way in any mode I have been using so far.

Now I used the markdown mode for the first time and it behaves as if 
tab-width was 4. I checked the variable value, and it is 8. Can somebody 
tell me how to get this right?
--
Frank