fix: avoid regex error if symbol chars used

        }

        else {

          // update search

          let mention = val.substring(this.startPos, pos);

          let mention = val.substring(this.startPos + 1, pos);

          if (event.keyCode !== KEY_BACKSPACE) {

            mention += charPressed;

          }

          let regEx = new RegExp("^" + mention.substring(1), "i");

          let matches = this.items.filter(e => e.match(regEx) != null);

          let searchString = mention.toLowerCase();

          let matches = this.items.filter(e => e.toLowerCase().startsWith(searchString));

          this.searchList.items = matches;

          this.searchList.hidden = matches.length == 0 || pos <= this.startPos;

        }