I'm sorry but you seem to be skirting the issue here... the width needs to be as it is... but the dropdowns need to know to flow onto the next line without a linebreak...
You seem unwilling to say that it is an issue with your css, and that at this time the fix is to either have a linebreak or increase the width some how.
I could live with that... in the hope that you are able to add to your list of bugs/ undocumented features that should be fixed in the next iteration...
We've not had this issue in v5 releases, so v6 seems to be the cause?