With the change in 8.0 that allows multiple Library windows to be open, my old standby, Ctrl+L, for bringing the Library back to the front (I always keep it in a maximized floating window), now opens another Library window. I find this proliferation of Library windows kind of annoying. The whole point of keeping the Library open in a floating window is that it's easy to get back to it without it taking up screen real estate in the main Logos window. I could Alt+Tab back and forth if the only thing I was doing was working in Logos. But I often have several other things I'm juggling at the same time -- a Word document, email, web browser, etc. So the Library often gets pushed further down the z-order of windows, and it takes an indeterminate number of Alt+Tabs to get back to it, and you've got to pay attention. I loved Ctrl+L because it was so simple. Just one keystroke and voila, you're back to the Library.
I'm voicing this as a complaint, but I'm not sure I have a suggestion for how to fix this that wouldn't ruin the ability to have multiple Library windows when you want them. I'm not sure I'd ever want them, personally, but I wouldn't want to ruin that for others.
Perhaps you could provide a new keystroke, Ctrl+Alt+L, that would bring the existing floating Library window up to the top if one exists, and open a new one if not.