Sysex Edit behaving strange in Web Editor

I’m encountering weirdness in the Sysex editor part of the Web Editor:

It seems to generate extra entries when switching entry types:

When I enter a few Constant byte entries but then switch to Parameter value I seem to get an extra Constant byte entry, the same when I switch back to Constant byte after the Parameter value. (I get an extra Parameter value.)

Quite possibly I have not mastered this section yet and I’m doing this wrong.