Hi Roberto! Thanks for reaching out! We haven't had any reports of issues like this so I am thinking it may be related to the internet connection or web browser you are using. Would you mind trying a few quick steps for us?
1. Make sure you're on a fast, reliable internet connection.
2. Make sure you're using the most recent version of your browser. We recommend Google Chrome for optimal performance.
3. Try browsing in a Chrome Incognito window. This will disable your extensions and cookies, which often improves performance.
4. Try turning off WebGL. This can be done by going to View > Use WebGL and un-selecting this option.
If these steps don't help, please fill out this form with as many details as possible of the issue, including:
1. A screenshot of the issue that is happening.
2. The URL to your document.
Thanks in advance for your help and patience!