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.

viewport,
        linkService: parameters.linkService,
        downloadManager: parameters.downloadManager,
        imageResourcesPath: parameters.imageResourcesPath || "",
        renderForms: parameters.renderForms !== false,
        svgFactory: new DOMSVGFactory(),
        annotationStorage:
          parameters.annotationStorage || new AnnotationStorage(),
        enableScripting: parameters.enableScripting,
        hasJSActions: parameters.hasJSActions,
        fieldObjects: parameters.fieldObjects,
        mouseState: parameters.mouseState || { isDown: false },
      });
      if (element.isRenderable) {
        const rendered = element.render();
        if (data.hidden) {
          rendered.style.visibility = "hidden";
        }
        if (Array.isArray(rendered)) {
          for (const renderedElement of rendered) {
            renderedElement.style.zIndex = zIndex++;
            AnnotationLayer.#appendElement(
              renderedElement,
              data.id,
              div,
              accessibilityManager
            );
          }
        } else {