Please, can someone explain what this little circle near the chord is? I didn’t find anything in the guide. Thanks.
Welcome to the forum, Claudio. Please consider changing the default format for screenshots on your computer to be a bitmap format such as PNG rather than PDF, since PDFs cannot be rendered directly by the browser and it becomes necessary for people to click the link to see the image.
To answer your question, it is a Write mode drag handle. If you click and drag it out to the right, it will show an extender line. Please refer to the Dorico 6 Version History PDF for more information about chord symbol extender lines.
Ahhh, ok, I get it 
. Thanks for the reply.