Different Idem font shapes in biblatex-dw

I have a problem with the font shape of the idem words in biblatex-dw.

In the MWE one sees that the word Ders in the first footnote is typeset in smallcaps with the original processed word being ders in lowercase.

In the second footnote Ders is also typeset in smallcaps, but with the original processed word being Ders so with a capital first letter. This has the effect that it looks different than the initial one.

The URL text is fine to be typeset as smallcaps with the original processed word being url.

I would like both Ders to be typeset the same. For this I tried to redefine the \mkbibmacro making the uppercase acronym first lowercase, then capitalize the first letter and finally setting it in smallcaps. However, the \MakeCapital doesn't seem to work. And even if it would work I think the URL would be effected to.

\documentclass{article}
\usepackage[backend=biber,style=footnote-dw,xref=true,mincrossrefs=1,edsuper=true,autocite=footnote,ibidtracker=constrict,idemtracker=constrict,ibidpage=true,namefont=smallcaps,citedas=true,annotation=true,idemfont=smallcaps]{biblatex}
\usepackage[ngerman]{babel}

\renewcommand*{\mkbibacro}[1]{\textsc{\MakeCapital{\MakeLowercase{#1}}}}

\begin{filecontents*}{MWE.bib}
@Collection{ABC,
editor = {Cornelisse, J. W.},
title = {Rocket Propulsion and Spaceflight Dynamics},
year = {1979},
gender  = {sm},
publisher = {Pitman},
}

@InCollection{ABC2,
crossref    = {ABC},
author = {Cornelisse, J. W.},
title = {Rocket Propulsion II},
year = {1979},
gender  = {sm},
publisher = {Pitman},
}
\end{filecontents*}

\bibliography{MWE.bib}

\begin{document}
Second book\autocite[][]{ABC2}. \textsc{ders} should look like \textsc{Ders} but \textsc{url} is fine

First book\autocite[][]{ABC} where \textsc{Ders} is typeset correctly.

\end{document}


biblatex-dw actively disables the automatic capitalisation tracker for "idem" in editor and translator position with \midsentence*. The following MWE re-enables it. The definitions of useeditor and usetranslator are copies from standard-dw.bbx with just the \midsentence* removed.

Since "idem"/"ders." is not an acronym \mkbibacro has no word in the formatting. The code below shows that the formatting is controlled by \mkidem, but there is no need to redefine that macro here.

\documentclass{article}
\usepackage[backend=biber,style=footnote-dw, xref=true, mincrossrefs=1, edsuper=true, autocite=footnote, ibidtracker=constrict, idemtracker=constrict, ibidpage=true, namefont=smallcaps, citedas=true, annotation=true, idemfont=smallcaps]{biblatex}
\usepackage[ngerman]{babel}

\makeatletter
\renewbibmacro*{useeditor}{%
\ifnamesequal{author}{editor}
{\ifbool{bbx:edbyidem}
{\bibstring[\mkidem]{idem\thefield{gender}}%
{\printnames[byeditor]{editor}%
\usebibmacro{editorstringpunct}%
\savefield{namehash}{\bbx@lasthash}}}%
{\printnames[byeditor]{editor}%
\usebibmacro{editorstringpunct}%
\savefield{namehash}{\bbx@lasthash}}%
\usebibmacro{editorstrg}%
\clearname{editor}%
\setunit{\labelnamepunct}\newblock}

\renewbibmacro*{usetranslator}{%
\ifnamesequal{author}{translator}
{\ifbool{bbx:edbyidem}
{\bibstring[\mkidem]{idem\thefield{gender}}%
{\printnames[byeditor]{translator}%
\usebibmacro{editorstringpunct}%
\savefield{namehash}{\bbx@lasthash}}}%
{\printnames[byeditor]{translator}%
\usebibmacro{editorstringpunct}%
\savefield{namehash}{\bbx@lasthash}}%
\usebibmacro{translatorstrg}%
\clearname{translator}%
\setunit{\labelnamepunct}\newblock}
\makeatother

%\usepackage{filecontents}
\begin{filecontents*}{\jobname.bib}
@Collection{ABC,
editor    = {Cornelisse, J. W.},
title     = {Rocket Propulsion and Spaceflight Dynamics},
year      = {1979},
gender    = {sm},
publisher = {Pitman},
}
@InCollection{ABC2,
crossref  = {ABC},
author    = {Cornelisse, J. W.},
title     = {Rocket Propulsion II},
year      = {1979},
gender    = {sm},
publisher = {Pitman},