If I have a directory containing some .wavs, some of which are valid IRs, some of which aren't; then if I accidentally arrow to an invalid file, NAM raises its error dialog, and I can't continue scrolling unless I re-select the folder.

Minimally, it shouldn't lose its place. Ideally, it might skip over those files when browsing with arrows (not sure what to do with the popdown menu. Keep it there, remove it, or show it, but disabled? Perhaps the last is ideal.)

May escalate if this looks like a big nuisance.