window.external.editdisc parameter questions

window.external.editdisc accepts the following values for the second parameter (I've indicated, for those interested, the sheet corresponding to each parameter; IOW, set the parameter to the indicated value to open the sheet named in the parentheses)

0 (general)
1 (tracks)
2 (artwork)
3 (credits)
4 (notes)
5 (custom 1)
6 (general)
7 (musicians)
8 (recording)
9 (library)

I have two questions.

1) Is there a parameter value for opening the 'misc' tab?

2) I have followed the examples and left the first parameter set to zero. But curiousity compels me to ask: what does the first parameter do? As far as I can tell from a few quick tests, any value except zero and you don't get a property page at all...

Thanks.