$(SciteUserHome) and $(SciteDefaultHome) should be independently and explicitly settable via environment variables.
Currently (on Windows), we can tell SciTE to read session and user properties files from a location () that is either the user profile directory (%USERPROFILE%), or from the same directory as the global properties file (via %SciTE_Home%).
Having the session and user properties files located in a different folder than the global properties () enables both easy backups and easy updates of SciTE itself.
Having them in a folder that is DIFFERENT from the user profile directory would enable the use of SciTE from a thumb drive.
Alas, the only documented way to achieve the latter is by giving up the former: If we set %SciTE_Home%, it will become the location of both user and global properties, preventing easy backups and updates. It's a "win-loose" situation.
Making it possible to set both locations independently would enable both aspects - a win-win situation.
Thanks in advance for consideration.
SciTE already maintains two variables to keep track of the two locations: $(SciteUserHome) and $(SciteDefaultHome).
My suggestion is to make it possible to set them via enviromnet variables
There is also the ability to access enviroment variables in properties files directly (i.e. $(FOO) expands to the value of %FOO%).
It seems natural to name the enviroment variables the same as the SciTE variables (i.e. %SciteUserHome% and %SciteDefaultHome%).