Side-by-side tabs
 

There's a discussion of an Ultra Recall-like app called TreeProjects on Outliner Software:

http://www.outlinersoftware.com/topi...-new-discovery

http://yp.lviv.ua/smereka/en/

It lacks many things offered in UR, which is still the leader in this genre, but one thing that especially appealed to me was the ability to drag a tab and have side-by-side tabs instead of having to view each tab individually.

I know being able to open multiple windows is on the roadmap (and that would be even better, I believe), I thought I'd mention it here in case side-by-side tabs would somehow be easier to implement ....

The awkwardness of working with multiple items at once is still my biggest issue with UR. Tabs help, but still you have to flip back and forth between them.