Useless horizontal scrollbar on JCommune non-English main page when width is small

Steps to reproduce:

1. Go to JCommune  main page http://qa.jtalks.org/jcommune/
2. Choose Russian language.
3. Make window width 704 px or smaller.
4. Point at the Feed subscription button.

Actual result: horizontal scrollbar appears.

Expected result: no horizontal scrollbar appears.

Additional info:

This horizontal scrollbar also appears when you point at the nickname of a person who left the last reply in a branch. The longer the nickname, the wider can be the window to display the scrollbar. This is valid for the Ukrainian language except for the scrollbar appearance by pointing at the Feed subscription button.

Version:

JCommune 3.13.3180.ed3a86a