BUG: Illegal Invocation error when using keepEmptyTextNodes

Version: 0.16.44

Are you able to reproduce the bug from the demo?

• Yes
• No

Set editor.Parser.getConfig().keepEmptyTextNodes = true; in the console and then attempt to drag a form into a 2 column plugin.

What is the expected behavior?

Describe the bug detailed From my observation a keepEmptyTextNodes will throw an error with Sorter.js when a droppable attribute is defined. When it tries to figure out validity it ends up getting the actual text node ahead of the content which means that the matches comparison fails (text node doesn't support matches).

What is the current behavior? Problem area seems to be the below in Sorter.js

        const tempModel = comps.add(dropContent, { ...opts, temporary: 1 });
        dropModel = comps.remove(tempModel, opts);
        dropModel = dropModel instanceof Array ? dropModel[0] : dropModel;
        this.dropModel = dropModel;

This is due to the tempModel then having the text nodes that may wrap the content defined in the block. When it is removed to obtain the dropModel we end up with the text node and not the actual content because of the parsing options.

Describe the bug detailed Attempt to drop plugin 2 into plugin 1 and note an illegal invocation error in the console.

https://codepen.io/neilkyoung/pen/abBxqmY

Are you able to attach screenshots, screencasts or a live demo?

• Yes
• No

https://codepen.io/neilkyoung/pen/abBxqmY

https://user-images.githubusercontent.com/3243711/111464171-5762f500-8718-11eb-9765-11d394c2c581.mp4