Remove transition from left panel header.
Fixed collapsed panel tab change.

It's kinda hackie, I need to find a proper fix.
Added keyboard shortcuts.

command: 'split vertically',   binding: 'ctrl+alt+v'
command: 'split horizontally', binding: 'ctrl+alt+h'
command: 'merge splitview',    binding: 'ctrl+alt+m'
command: 'create new file',    binding: 'ctrl+alt+n'
command: 'collapse sidebar',   binding: 'ctrl+alt+c'
command: 'expand sidebar',     binding: 'ctrl+alt+e'