Hi @Mohammad Amiri, thank you for posting in the community. Would you mind trying the following troubleshooting step to help us narrow down the potential cause?

• Open your document in a Chrome incognito window. Doing so disables extensions and clears cache and cookies, which often improves performance. This may also help you identify an extension causing an issue with Lucid performance.

If that doesn’t help resolve the issue, could you please share the following information?

• A screenshot of the issue. 
• The browser and version you’re using to access Lucid. 

Thanks in advance for your help! Please feel free to let me know if you have any questions. 

It appears that the grammarly extension causes the problem.
this extension checks all the text’s grammar in the browser.

Hi @Mohammad Amiri, thank you for the update, I’m glad to hear those steps helped you find the cause of the issue!

Please feel free to let us know if you have any other questions!