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.

["mouseenter", "Mouse Enter"],
            ["mouseleave", "Mouse Exit"],
            ["mouseup", "Mouse Up"],
          ],
          event => event.target.value
        );
      }
      if (blurListener) {
        element.addEventListener("blur", blurListener);
      }
      if (this.data.comb) {
        const fieldWidth = this.data.rect[2] - this.data.rect[0];
        const combWidth = fieldWidth / maxLen;
        element.classList.add("comb");
        element.style.letterSpacing = `calc(${combWidth}px * var(--scale-factor) - 1ch)`;
      }
    } else {
      element = document.createElement("div");
      element.textContent = this.data.fieldValue;
      element.style.verticalAlign = "middle";
      element.style.display = "table-cell";
    }
    this._setTextStyle(element);
    this._setBackgroundColor(element);
    this._setDefaultPropertiesFromJS(element);
    this.container.append(element);
    return this.container;
  }
}
class CheckboxWidgetAnnotationElement extends WidgetAnnotationElement {