"tabbed" view of diagrams

[Allan Gottlieb <gottlieb nyu edu>]

A while ago I read in this group how to have dia (which I love and use
regularly, thank you for the development) have one tab per open diagram
and all the tools on the same window.  I adopted it on my main machine
and it works great.

I now would like to use that view on another machine.
However, I am embarrassed to say, I can't find anything in the any of
the "file edit view ..." menu items that do it.  I checked
file/preferences twice, read the help, googled a little, etc.
I am sure it will be obvious when you remind me.

thanks again,
allan