Samana Johann wroteJust one thing, if it is so, that this code renders both id and anchor-link, why would it (didn't) not match (e.g. change the id, Both, for headers and anchors, before.)?
Oh, I did not read this before.
What I wrote was not very clear. What I meant was that both
1. id of
section anchors (i.e. the id of the heading defined with "==== Section Title ====" syntax in Wiki code)
2. and the anchor (behind '#') part of DokuWiki internal links, i.e.: "[[namespace:page#id]]"
are processed by the same function "sectionID" (which removes the dots)
Anchorlink: [[#mv.01.01]]
would become (simplified):
<a href="#mv0101">mv.01.01</a>
and
==== mv.01.02 ====
would become (simplified)
<h2 id="mv0102">mv.01.02</h2>
(dots removed)
This is only for the standard DokuWiki syntax of sections and internal links, which are modified by the "sectionID" function.
But there other ways of defining anchor ids directly, like this from the example you gave on the test page (I think this is using the wrap plugin):
<span #mv.01.01>Text with anchor id mv.01.01</span>
will become/stay
<span id="mv.01.01">Text with anchor id mv.01.01</span>
(dots not removed)
The wrap plugin '#' syntax directly sets the id of an element without removing any dots or changing anything. But one can not link to them with standard DokuWiki "[[namespace:page#id]]" internal link syntax if there are dots. It is a bit confusing that it looks very similar to the DokuWiki internal link syntax with the hash '#' character.
Maybe that is where the original problem here came from (at least that is the problem that the test page illustrates): section header ids and internal links defined with normal Wiki syntax are processed by the "sectionID" function. And so of course they both match (removing the dots). The problem comes in when one has other ids defined not through Wiki sections, which contain dots, like the last example here with the wrap plugin.
But all this has not much to do with the Hidden Header plugin. A hidden header would render the id in the same way as a normal header. (with dots removed in current standard DokuWiki)