Editor Tab navigation does not work for some files.

[hyukmin-kwon]

Editor Tab navigation does not work for the following cases

• Example editors, image viewer
• Javascript files in which ES6 arrow function with expression is used.

[hyukmin-kwon]

• The case, Javascript files in which ES6 arrow function with expression is used, is solved by follwoing commit.
  • [TASK] Use calcium that supports arrow functions.
  • Exception in assist worker is the cause.

[hyukmin-kwon]

• For the case, Example editors, image viewer, there is not proper initialization for shotrcuts.

[hyukmin-kwon]

• We will close this issue and remaining issue for Example editors and image viewer will be treated as separated issue Editor Tab navigation does not work for some editors. #635