You say that you can selectively exclude images from oipening in a modal window by adding rel="nofloatbox" (pre v3.50) or class="nofloatbox" (v3.50+) to the anchor tag. According to my testing neither of those work. What I did discover is that you have to have *both* class and rel (order doesn't matter) *before* the href attribute. The attributes can have any value (except "floatbox"), or you do not need values at all. Strange, but that's the only way it seems to works for me. I'm OK with that.
Floatbox also seems to have changed the behavior of a NextGen gallery. I can no longer cycle through a gallery of images in the same modal window, as each separate image now only opens in it's own modal window <sigh>. I'm not OK with that. Any ideas?