After a while of working with Lightroom with the extra catalog, I still found it a pain that if I just click the Lightroom app icon, then it would hang (since it was trying to load the previous catalog).
So I've taken the extra step of selecting the new catalogue as the default catalogue - look for "Always load this catalog on startup" when you start with Alt-clicking the icon. Works a treat now.
Change to the new Catalog
After a while of working with Lightroom with the extra catalog, I still found it a pain that if I just click the Lightroom app icon, then it would hang (since it was trying to load the previous catalog).
So I've taken the extra step of selecting the new catalogue as the default catalogue - look for "Always load this catalog on startup" when you start with Alt-clicking the icon. Works a treat now.