I18NEdit knows another search mode in which it lets you search for a certain word or phrase in the locales. This is perfect e.g. when you discovered a misspelling but don't know exactly where it is.
Select "Search → Search string". A dialog opens where you can setup your search.

String search preparation
On the left, select all locales in which the string in question should be searched for.
On the right, enter the string and select whether the search should be case sensitive or restricted to whole words. You can also search for regular expressions, in which case the "whole word" flag is not considered (the "case sensitive" flag, however, is).
Press "Search" and I18NEdit will start searching for the first occurrence of the search string or pattern from the currently shown property on forward.

Item presentation in string search mode
During string search, all locales which are included into the search are shown with a blue background.