mid-measure RehearsalMark

[Kieren MacMillan]

Hello, all --

In the doc RehearsalMark section, it says: "If you specify it in the  
middle of a bar, the resulting mark is positioned between notes." But  
this means LITERALLY, e.g., no notes appear under the \mark text itself!

This looks silly:

%%%  CODE SNIPPET ENDS
\version "2.9.9"
\paper { ragged-right = ##t }
\relative c'
{
        \override Score.RehearsalMark #'self-alignment-X = #-1
        c4 c \mark \markup "some fairly significant marking" c c
}
%%%  CODE SNIPPET ENDS

Is there a fix/workaround for this? Or does nobody else ever use a  
mid-measure RehearsalMark?

Thanks,
Kieren.