I encountered the same problem. Vista Disk management let me shrink my
left most partition (L

wwhich created free nonallocated space between
my leftmost partition and my rightmost partition (R

. when truing to
exppand my rightmost partition (R

into the free space on its left,
Vista insisted to convert my disk to a dynamic disk, would not work
otherwise. This was the case both when R: was a primary partition and
when R: was a logical partition within an extended partition. Converting
the disk to a dynamic disk is not a good idea if it contains the
operative system why I had to abort the operation. Seems Vista will
expand without convertion to a dynamic disk only if the free space is to
the right of the expended partition. Naughty Vista.
--
AdamBerko