Uncaught TypeError: Cannot read property 'length' of undefined

[vivi90]

[Enter steps to reproduce:]

1. Open new Atom window.
2. Try to add new music track.

Atom: 1.45.0 x64 Electron: 4.2.12 OS: "Manjaro Linux" Thrown From: mitsu package 0.11.0

Stack Trace

Uncaught TypeError: Cannot read property 'length' of undefined

At /home/vivien/Projekte/mitsu/lib/player-view.coffee:166

TypeError: Cannot read property 'length' of undefined
    at PlayerView.module.exports.PlayerView.filesBrowsed (/home/vivien/Projekte/mitsu/lib/player-view.coffee:166:7)
    at HTMLInputElement.<anonymous> (/home/vivien/Projekte/mitsu/lib/player-view.coffee:1:1)
    at HTMLInputElement.dispatch (/packages/editor-background/node_modules/space-pen/node_modules/jquery/dist/jquery.js:4435:9)
    at HTMLInputElement.elemData.handle (/packages/editor-background/node_modules/space-pen/node_modules/jquery/dist/jquery.js:4121:28)

Commands

     -0:15 mitsu:toggle (input.hidden-input)

Non-Core Packages

atom-browser 1.7.0 
atom-ide-terminal 5.0.1 
atom-ide-ui 0.13.0 
mitsu 0.11.0 
atom-ternjs 0.20.0 
autocomplete-java 1.2.7 
autocomplete-javascript 0.0.2 
autocomplete-sql 0.5.0 
busy-signal 2.0.1 
editor-background 1.2.42 
example 0.0.0 
file-icons 2.1.40 
highlight-colors 0.9.0 
hyperclick 0.0.0 
ide-cpp 0.1.0 
ide-java 0.9.0 
ide-php 0.7.18 
intentions 1.1.5 
java-generator 2.2.3 
language-assembly 0.7.2 
language-haskell 1.19.4 
language-latex 1.2.0 
language-lsl 2.2.0 
language-vhdl 0.7.2 
latex 0.50.2 
latexer 0.3.0 
linter-javac 1.10.0 
pdf-view 0.72.0 
php-ide-serenata 5.2.0 
plantuml-toolkit 0.2.0 
project-manager 3.3.8 
quick-query 1.1.1 
quick-query-sqlite 0.3.2 
teletype 0.13.4 
xilinx-unisims 0.1.0 

[vivi90]

I am unable to fix this issue.