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.

name: "Keystroke",
              value,
              willCommit: true,
              commitKey,
              selStart: event.target.selectionStart,
              selEnd: event.target.selectionEnd,
            },
          });
        });
        const _blurListener = blurListener;
        blurListener = null;
        element.addEventListener("blur", event => {
          const { value } = event.target;
          elementData.userValue = value;
          if (this._mouseState.isDown && elementData.valueOnFocus !== value) {
            
            this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
              source: this,
              detail: {
                id,
                name: "Keystroke",
                value,
                willCommit: true,
                commitKey: 1,
                selStart: event.target.selectionStart,
                selEnd: event.target.selectionEnd,
              },
            });
          }
          _blurListener(event);