Assets with a negative value treated as zero in reports

[Colin Bell]

When I do an Account Summary report, any asset I have with a negative 
value (such as an overdrawn bank account) is treated as having zero 
value. This seems to apply to all the Asset and Liability reports.

I assume this behaviour is by design, although it seems broken to me.

Is there an option to turn this off and get a correct balance sheet for 
my accounts?

Thanks,

Colin