Attach (recommended) or Link to PDF file [here:] Can't see how to attach a pdf here, but it is simple to create. Add a form object textbox to a pdf and make sure the option for "Multiline" is true.

Steps to reproduce the problem:
1.  Open a document with a Textbox that is set to Multiline.
2. Attempt to hit the Enter key to go to a new line.

What is the expected behavior? The cursor goes to a new line.

What went wrong? It does not go to a new line.

Link to a viewer: It can be reproduced on mozilla.github.io/pdf.js

I corrected the issue by altering the pdf.js file like this
element.addEventListener("keydown", event => { 
[...]
--} else if (event.key === "Enter") {
++ } else if (event.key === "Enter" && !this.data.multiLine) {

Our initial testing is coming through clean, and hopefully something like this code can be committed to the project in the future.

const r = BACKGROUND_ENLIGHT * (255 - color[0]) + color[0];
      const g = BACKGROUND_ENLIGHT * (255 - color[1]) + color[1];
      const b = BACKGROUND_ENLIGHT * (255 - color[2]) + color[2];
      popup.style.backgroundColor = Util.makeHexColor(r | 0, g | 0, b | 0);
    }
    const title = document.createElement("h1");
    title.dir = this.titleObj.dir;
    title.textContent = this.titleObj.str;
    popup.append(title);
    
    
    
    const dateObject = PDFDateString.toDateObject(this.modificationDate);
    if (dateObject) {
      const modificationDate = document.createElement("span");
      modificationDate.className = "popupDate";
      modificationDate.textContent = "{{date}}, {{time}}";
      modificationDate.dataset.l10nId = "annotation_date_string";
      modificationDate.dataset.l10nArgs = JSON.stringify({
        date: dateObject.toLocaleDateString(),
        time: dateObject.toLocaleTimeString(),
      });
      popup.append(modificationDate);
    }
    if (
      this.richText?.str &&
      (!this.contentsObj?.str || this.contentsObj.str === this.richText.str)
    ) {
      XfaLayer.render({
        xfaHtml: this.richText.html,