#2 Filter by "contains" not "equals"

[mercury]

I use the filter option to search my accounts for transactions. The filter
for "description" seems to be:
1. case sensitive (that's good)
2. matches exact position (that's bad)

for example if my transactions are:

Bill for Nov
Payment to Loser
Large expense

.. and I type 'l' in the description field; it only matches the "Large
expense", whereas it could match Bil'l' as well as 'L'oser

Without this, the filter based on description is NOT very useful, since
people hardly remember the exact description.