Vlad Thanks for the new development. I tested this feature out in the new beta. Unfortunately it didn't work as expected. When Last Active Profile is checked, if I open two profiles A and B together, A at first and B at last, then the external links are always opened in B--the last profile that I opened, rather than A--the last profile that I just clicked on and did some web browsing in, no matter if A and B are in the same space.
Also, I kinda wonder how you define this "last active" for a profile. I thought it would be the profile window in the current space that I most recently used.