Subtitles, Languages, Chapters

When an MKV file has a subtitle, alt language, or chapter information, the "info" mode that prints the title at the top and the progress bar at the bottom should also indicate with very small icons that there is alternate content accessible with the 'subtitle' or 'language' buttons.

Which button could 'chapter' go on though? Right now you can allegedly select the "chapter" by selecting 0-9 (which gives you a percentage interval.) Perhaps you could press '.' or 'enter' during viewing and it would pop a chapter list in a scrolling menu?

I thought it would be neat to have chapter entries with images, but that isn't part of the MKV XML spec for chapters apparently.