Can't think how I never noticed this before.
I've been after something that can do exactly what this does for ages. Specifically, since I noticed that I couldn't find a way to make runas work in other tools I use.
My first impression was slight confusion -- I think you have to have read the initial request and at least some of that background, and I found some of the screenshots helpful and illuminating too. Probably fullblown documentation is unnecessary but maybe a couple of lines of text with a brief description of what each of the fields is typically going to be used for, and a couple of complete examples maybe:
For instance, if I want a button that runs Active Directory Users and Computers as a user with admin privileges from an account without them, you might have:
Image file: <sysroot>System32\mmc.exe;0
Command prefix: runas /user:domain\superuser "<sysroot>System32\mmc.exe dsa.msc"
Button caption: something like "AD Users"
and Button tooltip: "Active Directory Users and Computers"
and "Ignore variable text" checked as this one's probably gonna have to be run locally
along with a little bit of explanation that, at least for its intended purpose, the variable's going to be the remote machine you're aiming the command at rather than anything else, everything would have fallen into place fairly quickly.
If I had a suggestion for a possible improvement: a checkbox that will assume the use of runas and a little bit of program allowing a username and password to be stored and easily amended with a view to adding them to the runas command in the appropriate place without displaying it in cleartext, that'd be rather lovely.
But in general: wonderful! Thanks!