KMTTP

24 minutes ago, Canopus said:

It’s not a bug. The controls displayed will depend on the width of the pane. Just make the pane a tad wider by grabbing the left-hand edge and drag it to the left and all the buttons will show up.

Thank! 

I've never seen a bug like this before.
You can see solo mute button in the piano roll view track pan.
Windows updates, driver updates, etc. have not been done recently.
It suddenly disappeared.
I reinstalled it. But I can't see it.
How do we deal with this?