Modern Editor: Inserting a line break <br> instead of a paragraph tag <p>.
When you are writing text into the text content editor using the return key will add a paragraph tag <p> to your content which creates a larger space between the text above and below.
In order for the content to flow directly below the content above it, a line break needs to be added to the content. To add a line break <br>, use the key command shift+return.
*For the same behavior in the Safari browser, click control+return. All other browsers use shift+return.