Yes, you can control whether formatting is retained for pasted text into the drag-and-drop editor. This is a setting on the individual administrator record.
1. Click Settings icon > select User Management.
2. Locate and click Account Administrators (left column). If you are a Site Administrator, click the Site Administrators tile instead.
3. Locate your administrator record and click 'Edit' button (right side).
4. On the opened record, scroll to the bottom of the page.
5. Locate and check "strip all formatting when copying from clipboard".
6. Click Save.