Before and after the patch:
1. In Lokalize, open a translation project with a large
number (> 999) of files. (The project at trunk/l10n-support/nn
in SVN is a good candidate).
2. Look at the status bar. Notice that large numbers
are missing the thousands separator (e.g. a comma or
space, depending on your locale) before the patch
but are properly formatted (i.e. with a thousands separator)
after the patch.
3. Open a file that contains a large number of strings
(extragear-edu/kstars.po is a good candidate).
Notice the lack of proper formatting before the patch,
but proper formatting after the patch.
BUG: 394866