[plt-scheme] more on 299.100

Tabs are quite nice, especially the option to automatically open new 
files in them. Great for laptop screens. However, is it possible to have 
Interactions windows be specific to tabs? At present it seems if I am in 
a full-window Definitions tab, then switch to another tab and run a 
program, when I go back to the first tab, the Interactions window is 
open still, and I have to type command-E to close that and get the first 
tab back to the state in which I left it. I seem to be doing this a lot 
today. Thanks. --PR