Keep Multi-Series browser open

[DrDaleks]

A feature request from "close" neighbours :)
On a workstation with little RAM, a multi-series dataset usually doesn't fit in memory, so you can usually have only one dataset opened at a time.
The trouble is the multi-series browser takes time to load (due to the parsing process), so reopening all the time to load each dataset separately is a nightmare.
Keeping the browser open (and opening by double-clicking on the thumbnails) would be great!