Show number of audio channels on "Select file to add" window
In the mkvtoolnix gui, in the window with the title "Select file to add" which has "Select one or more playlists to add" at the top, the "Tracks" list under "Details" should be expanded to show how many audio channels are present for each audio track.
This would really help with ripping audio from surround sound music blu rays. Often they feature both some surround sound and some stereo content, so it would really help to quickly identify which is which.