Thanks for looking into it!

It is entirely possible this was broken by AuthManager changing a hand-made template to HTMLForm. I compared visuals at the time but this text is not visible by default so I might have missed it.

I am not sure the old positioning is easily achievable, but at the very least it should look like it belongs to the username, not the password.

Change 306740 had a related patch set uploaded (by Bartosz Dziewoński):
LoginSignupSpecialPage: Restore old display of 'createacct-helpusername'

https://gerrit.wikimedia.org/r/306740

Change 306740 merged by jenkins-bot:
LoginSignupSpecialPage: Restore old display of 'createacct-helpusername'

https://gerrit.wikimedia.org/r/306740

Here to report that some users can experience an issue with the floating user name tip:

Some circumstances:

1. Users who incremented font size in browser preferences (e.g. accessibility reasons)
2. Vendor customizations / non-standard browsers (Mozilla Firefox 39.0 seems affected, or pherups only by Ubuntu customizations)
3. Specially on wikis with more than few characters in MediaWiki:Createacct-helpusername (e.g.).

Firefox 39.x saw its end of life on August 11, 2015. If anyone is still running such an ancient insecure version they have much bigger problems, I am afraid =)

Yep!

(...and now the funny part: for years people insanely cared a lot about supporting ancient insecure versions of Internet Explorer :^)

In T143923#3804732, @valerio.bozzolan wrote:

Here to report that in Mozilla Firefox 39.0 the text seems rendered somehow bigger than normal and so in it.wiki I see this text wrapped.

https://it.wikipedia.org/w/index.php?title=Speciale:CreaUtenza

I cannot reproduce this problem with other newer versions of Mozilla Firefox, or with Chromium 43.0, so it seems only a bug in Mozilla Firefox 39.

The bigger text is probably because it's using a different font than most systems, I've seen this on many computers running Ubuntu (regardless of the browser). I get a similar effect on my machine when I change the font to Verdana – however, the text does not overlap the field, it pushes it down.

If you're using Firefox 39 and want to fix this, I'd be happy to accept a patch (as long as it's simple), but don't expect anyone else to set up an old browser and experiment with it :)

Thinking on it generically, the problem is that we shouldn't rely on [[MediaWiki:Createacct-helpusername]]. If it's customizable it means that it shouldn't break the alignment when longer than the expected by the web designer.

For now, I think that locally we could simply avoid floating stuff:

#userloginForm .loginText span {
	float:none;
}
#userloginForm .loginText span:before {
	content: ' ';
}

Or at least, with that small compromise:

#userloginForm .loginText span {
	float:none;
	font-size:11px;
}
#userloginForm .loginText span:before {
	content: ' ';
}