Broken: blender-2.80.0-git.699193713fc0-windows64, 2.81, 2.82
Short description of error
Deleting the last keyframe in Grease Pencil Dope Sheet will leave the channel (where it should vanish).
This has following bad consequences:
When "View All" is performed in an empty Dope Sheet in Grease Pencil mode, it zooms in really far and scrolling is broken.
Upon zooming, it resets the view to frame 0.
Exact steps for others to reproduce the error
Execute "View All" (Home or Pos1 key) in the Dope Sheet.
Now try to pan the view (with middle mouse button). The Dope Sheet will sometimes go blank or jump to extremely high frame numbers.
Zooming out often resets the view to frame zero.