using the filter designer wizard

I occasionally review various online active filter design tools. Is there some detail in some document that describes where those min. GBW numbers come from. Specifically, if you take a 1MHz gain of 1 Butterworth 2nd order (single stage) design, and navigate to an MFB design and then try to change the amplifier, starting from this screen, hit change, 

I then get this where at the bottom I see two min GBW numbers - the lower one seems too low for this design, any idea where that is coming from?

If I go back and activate the adjust for GBW, I would expect these min numbers to change, but they don't. Maybe that 1.77Mhz is where it is assuming a GBW adjust in the RC values whereas the 7.08MHz is not? It does not seem any of the available op amps to change to are anywhere near this low on GBW. The slowest I see is 8MHz so still well above the required min 1.77MHz.