DirectVobSub Definition not Honored with WMP?

Hi,
Had some trouble playing a Divx file with WMP, while Media
Player Classic(MPC) played it well. the file just wouldn't play.
turned out it always happens when DirectVobSub is loaded.
well, it looked strange to me, because i'm using this combination
many-many times, so why now?
To make it short, my movie is 352X268 (W x H), and
#DirectVobSub General Resolution# was defined "Double
if smaller than 384X288". i changed it to "Original resolution",
and everything is OK now.
Question is, why the "Double.." definition is honored with MPC,
but not with WMP? the *same* DivX codec is used in both cases,
so, if it is a simple matter of 1+1=2, i'd say it's a bug in WMP,
but i have a feeling that it's not so simple.
any ideas?
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thanks
jacob