Steps to reproduce

1. Enable `source: true` to the richTextField
2. Open form contains the richTextField
3. Add a few images, 6 or 7 items
4. Switch to Source mode 

Expected results

• The editor's height remains as is when switching between modes
• The editor's content can be scrolled up/down without any issue

Actual results

1. The editor's height grows within the length of the content in the Source mode
          

1. When scrolling down in the Source mode, the browser returns an error