In mmg pressing F1 gives: """ The mkvmerge GUI help file was not found. This indicates that it has never before been opened, or that the installation path has since been changed. Please select the location of the 'mkvmerge-gui.hhp' file. """ $ ls /usr/share/doc/mkvtoolnix* /usr/share/doc/mkvtoolnix: guide /usr/share/doc/mkvtoolnix-5.0.1: AUTHORS.bz2 ChangeLog.bz2 README.bz2 TODO.bz2 media-video/mkvtoolnix-5.0.1 is installing two directories in /usr/share/doc and compressing the help files in /usr/share/doc/mkvtoolnix/guide. Fixed for me by adding to econf: --docdir=/usr/share/doc/${PF} and to src_install(): docompress -x /usr/share/doc/${PF}/guide
Same problem.
Fixed in CVS.