ngs.includes(errorString)) {
        return;
      }

      errorStrings.push(errorString);

      if (baseOneLineNumber < 1) {
        console.error(`addError called with bad line number: ${baseOneLineNumber} - remember it needs to be base 1!!`);
        return;
      }

      const msg = document.createElement("div");
      const lines = errorString.trim().split('\n');
      for (let i in lines) {
        const line = lines[i].replace(/ /g, '\u00A0');
        msg.appendChild(document.createTextNode(line))