What is the shorcut for minimizing(open/reopen) selected track pane?

Hello.
 
I'm wondering about two shortcuts.
 
1) I'm wondering if there are some shortcuts for minimizing(open/reopen) selected track pane.
I always have to click tiny arrow-shaped(two triangles in vertical) button on the right side of each tracks several times while working.
So I tried to search the shurtcut  for it but couldn't find.
Is there a shortcut for it or are there any methods to open/close(minimize) selected track simply?
(I found a shortcut like ctrl+shift+H but this makes track's height maximized instead of simply opening with certain height.)
 
2) I'm also wondering if there is a shortcut for switching between 'audio' and 'midi' in right bottom side of the inspecter of instrument track(one track including both midi and audio).
 
Thanks
JunL