Find the arithmetic operator

Simplest is instead of using

findGrepPreferences.findWhat

use

findTextPreferences.findWhat

The point is that + is a GREP symbol (meaning one or more times).

So if you really must use GREP, you have to escape it with a backslash

(and that backslash has to be escaped as well if you're scripting it):

findGrepPreferences.findWhat = "\\+";

But again, just use textPreferences unless you have to use the extra

power of GREP

Try this ...

app.findGrepPreferences.findWhat = "\\+";