I am a little cofused between the Call and Run commands.
I have a hidden worksheet (testfile.xls) that loads every
time excel is open (Note: Thisworksheet.isaddin = True &
Macro Security Level is set to Medium).

From a new workbook I want to create a button that calls
a subroutine, MySub(), from testfile.xls. I tried to use:
Call MySub()
but it was not recognized. After a little research, I
used:
Run "MySub()"
and it seems to work. My question is what is the
difference between the Run and Call Commands? I thought
they were essentially the same functions.