That's why I make that password extremely hard to brute-force, and memorize that.
As far as I know, that particular program isn't vulnerable to rainbow table attacks; it doesn't store a hash of the valid password, but uses it as a symmetrical encryption key. If you enter a wrong password, it can't tell the difference between "This is a valid file, but the wrong password," and, "This file is a bunch of gibberish that you typed in Notepad." The only way it can tell that it is the right password is if the decryption yields something intelligible.
I will admit, if someone got a hold of that file and was using a keylogger on my desktop or phone, I'm pretty well pooched.
On the other hand, if someone's using a keylogger on my desktop or phone, I'm pooched anyway.
Though, now that you mention it, I'd better change that password. It's probably overdue for it.