This is an old tip that I had forgotten. Before I mention please know(as you should already know from the title) that this is a Homesite tip. It also applies to the old "Coldfusion studio" if that's your cup of tea. I know I know - I should always use CF eclipse. I have it and I use it but my trusty Homesite is an old friend and I can't seem to completely say goodby. Plus at 43 it's hard to teach an old dog new tricks :)
In any case, these days many developers have 2 or three monitors. I have 2 wide screen monitors myself. I love being able to get lots of information on the screen at one time. Occasionally I have a need to see more than 2 file structures. I might even want to see 2 CF pages at once. This is something of a limitation in Homesite. I have to toggle back and forth between pages rather than being able to arrange them in my workspace (a la CFE). Fortunately there is a way to allow Homesite to open in multiple instances on my desktop.
Disclaimer: Remember that editing your registry incorrectly can wreak havoc on your PC and has been know to cause headaches, fever, world hunger, over population and sterility (those last two are ironic eh?). Find the registry branch under HKEY_CURRENT_USER\Software\Macromedia for Homesite+. Add the value "AllowMultipleInstances" and set it to 1. Close Homesite and then open it twice - Viola! You now have two instances.
In the old days HS was known as something of a memory hog. Back when 512 megs was a lot of memory the 30 to 50 meg footprint was significant. These days, however, HS has a small footprint compared to other tools you might already be using. I would wager that 2 instances of HS will run in less memory that 1 instance of Dreamweaver.