A slur (or tie) with the dotted property is rendered as a black 'solid arc' (not a line) both while printing and in .pdf export. This applies to 0.9.6 beta 2 and to rev. 2891, both under Windows and under Linux.

STR: look at the attached TestDotted.mscx, TestDotted_Linux.pdf and TestDotted_Win.pdf.
Printing from MuseScore reproduces exactly what appears in the PDF.

Thanks,

M.