This isn't quite a bug, although the text is excessively small, and that will be corrected. It's also not commented in the CSS, which will be corrected.
It's an intentional display rule for non-English, because words are often longer. It's fairly arbitrary, but on balance we thought having a default (customisable) rule was better than having words bleeding out of the edge of the menu.
Look for "{+START,IF,{$NEQ,{$LANG},EN}}" in global.css. It is there twice.
(Click to enlarge)
#1589 - Language selection shrinks text in side menu block
It's an intentional display rule for non-English, because words are often longer. It's fairly arbitrary, but on balance we thought having a default (customisable) rule was better than having words bleeding out of the edge of the menu.
Look for "{+START,IF,{$NEQ,{$LANG},EN}}" in global.css. It is there twice.