Hi,
I guess this prob will usually occur during flap retraction on T/O or during approach, so if there is a high workload, there won't be time to fiddle with the FMC.
The 777 flaps/slats alternate display sucks. You can see the flaps selected but you can't determine they are stuck between which stages during flap retraction when you just keep on commanding the PNF to retract whenever the speed is within limit.
Some suggest looking at the speed tape on the PFD, while some suggest others. I m quite confused now ;p
FD