NotesHound (http://www.noteshound.com/) is an inexpensive collection of useful tools from Ken Haggman and Daniel Lehtihet. We have mentioned the NotesHound Class Navigator, which is sold seperately for some time by now, in some conference sessions and recommended it strongly for OOP developers in Lotusscript.
In SnTT: Installing and running Notes R5, 6, 7 and 8 concurrently we described in details, how you can install different versions of Lotus Notes on one machine in a way, you can even start them concurrently. This way you avoid the additional cost of memory consumption and (OS) licence cost for VMs.
But there is a problem with all NotesHound tools - beside the NotesHound Class Navigator - in such an environment: You can only start the tools in the lastly installed version of Notes.
After analysing the problem with Ken, we found the root cause and a possible solution. In the front-end, the NotesHound tools use the COM interface to communcate with the Notes client. When you install a Notes client, its version of a certain DLL file - nlsxbe.dll - is registered system-wide and is resposible for the Lotus Notes COM interface from this moment on. At a time, there can be only one version of the DLL file be registered - normally that one, which belongs to the lastly installed Notes version.
With regsvr32 nlsxbe.dll, executed in the Notes program directory, you can manually install a certain version of the DLL file. Afterwards you can use all the NotesHound tools in this version of Notes.
I assume, in the near future the NotesHound programs will do this in the background, but in the meanwhile you can use a fast wordaround. I have written the batch file RegisterDLLAndStartNLNotes.cmd:
REM Batch file should be started with one parameter - the Notes program directory
CD /D "%1%"
%SystemRoot%\system32\regsvr32.exe /s nlsxbe.dll
START /MIN nlnotes.exe