Ulrike Fischer wrote:
> Am Sun, 1 Jun 2014 21:23:39 +0200 schrieb Frank Mittelbach:
>
>
>>> This code breaks the float package if fixltx2e is loaded afterwards.
>>> Which happens if one has the habit of loading packages alphabetically
>>> and invoking fontspec which requires fixltx2e. By this, documents with
>>> the header
>>>
>>> \documentclass{article}
>>> \usepackage{float}
>>> \usepackage{fixltx2e}
>>>
>>> \begin{document}
>>>
>>> will not compile anymore. Is this intended? Would it help or do any harm
>>> if the float check would be added \AtBeginDocument?
>
>> just checked: CTAN has the right file with version number 1.1q for
>> fix-cm and that file doesn't have the extra rubbish inside any longer,
>> so it looks like you still run the initial beta where the docstrip guard
>> was missing
>
> Arno wrote about fixltx2e and not fix-cm. And he is right: If loaded
> after float fixltx2e overwrites the float definition of float:
>
> \documentclass{article}
> \usepackage{float}
> \usepackage{fixltx2e}
> \begin{document}
> \begin{figure}[H]
> blub
> \end{figure}
>
> \end{document}
>
> gives:
> ! LaTeX Error: Unknown float option `H'.

Exactly this is the error I get. File list: (happens with pdflatex, too)

This is LuaTeX, Version beta-0.79.1 (TeX Live 2014) (rev 4971)

  *File List*
  article.cls    2007/10/19 v1.4h Standard LaTeX document class
   size10.clo    2007/10/19 v1.4h Standard LaTeX file (size option)
    float.sty    2001/11/08 v1.3d Float enhancements (AL)
fixltx2e.sty    2014/05/13 v1.1q fixes to LaTeX
  ***********

> I run into a similar problem some days ago: If loaded after setspace
> fixltx2e overwrite the setspace patches for floats.
>
> Imho fixltx2e should be loaded like fix-cm before documentclass to
> avoid such problems.

How would you then treat packages that require fixltx2e and are loaded 
at a later point? (As in your code example?)

best,
Arno