[GNC] Can I Prevent OFX/QFX Import Overwriting Notes?

[gcul209 at mynym.us]

I wouldn't be surprised if this has been asked in the past, but I don't 
know of a good way to search the archives for these mailing lists (seems 
I'd have to download a month at a time in order to search manually).  I 
also wouldn't be surprised if the answer is blatantly obvious / right in 
front of me and I'm just missing it.  I did try an Internet search and 
got too many irrelevant results (outside of the manual and basic import 
information, which I did look through a bit, without much luck).

I recently migrated from an old PC to a new Mac.  As far as I can tell, 
I was running GnuCash 2.6.16-1 on the PC (I don't remember why I stopped 
updating), but I figured I should upgrade during the transition, so I'm 
running 4.6-1 on the Mac.  I have always downloaded OFX and/or QFX files 
from my banks in order to reconcile my manual entries and import 
additional transaction data (using U+C to complete my register).  For 
the manual entries, I have always used the notes field in the register 
for most of my bank accounts because there's typically nothing worth 
importing there anyway (just something like "OFX ext. info: |Trans 
type:Generic debit").  Previously, on the PC, my manually entered notes 
were NOT overwritten.  Now that I'm on the Mac, the notes are being 
overwritten by that arcane data, but I don't know if that is a PC vs Mac 
thing or a version change thing.  I also don't know if there is anything 
I can do to prevent it in either case.  What I do know is that the 
behavior is consistent across file types and banks (I ignored it the 
first time it happened because I didn't want to re-enter a bunch of 
previous transactions in order to try to work around it, but I was 
expecting it this time, with a different bank providing the data, and 
confirmed it happens for both formats).

I don't really want to lose my manually entered data, but I would like 
to have the bank data imported an synchronized as well.  Is there 
anything I can do so that the generic transaction information doesn't 
overwrite my previously entered notes?