I've gotten a wrong message "Function JustExt() not found" or so in VFP6, at a place where it worked fine in all previous versions since FPD2.6; that's where I'm extracting the field name:

JustField=JustExt(thisform.controls[i].controlsource)

The message is wrong - it actually complains of not being able to pass a property to JustExt. Here's the workaround:

dummy=thisform.controls[i].controlsource
JustField=JustExt(dummy)

[no question asked here, I've just posted this, hoping it may save some time to someone else]