Use fat arrows

[JeroenVinke]

For example this can be written more compact:

this.content.addEventListener("cellFocus", () => this.content.focus());

or this:

this.content.onkeydown = (e) => {
      if (this.parent.readOnly() === true && e.keyCode !== 9) {
        return false;
      } else {
        if (!this.parent.editMode()) {
          return false;
        } else {
          return true;
        }
      }
};

[vegarringdal]

thx, some bad habits/parts that never made the clean up

[vegarringdal]

fixed