Hi Mark,
I have run across what I would call a small bug in the dialog to set properties. If I select multiple investments by selecting one and shift-clicking another, right click on the selected group and pick "Properties" and then "Other," and then change the "Hidden" attribute, only the first investment is changed. I haven't checked to see if other settings have the same issue, but you might want to put this on the fix list.
Thanks,
Ivan