I ran into this same problem, where the "search" field to enter the amount for the partial refund was not editable. I'm still not sure If I issued a full refund by accident or not, but will be be checking my bank statements.
But after a few tries doing the same thing a few times the amount field suddenly became editable and I was able to issue a partial refund.
Intuit, this is some godawful UI. And on top of that a really bad bug. And as seen within this thread a whole bunch of unhelpful customer support that doesn't know what is actually going on. And a sloooowwww development team that doesn't respond to customer complaints about software issues that can cause some very real problems for your customers.
This isn't the first time I've run into something like this with Quickbooks, so looks like I'll be looking for an alternative to this bloated, buggy mess backed up by poor customer support and unresponsive product development.
