when i launch em client 10, sometimes i have to close and reopen because it wont scroll properly in the email window.
I would suggest to remove eM Client from the Groupy docking / tab program and see if it scrolls correctly “as its not normally designed to work within other programs” or GUIs.
If eM Client then still won’t scroll emails properly and lagging and you are using the latest 10 via the release history page, then could be the emails are not fully cached / loaded 100% yet and there might still be eg: some external inline or other email external content loading in that email or other eM Client acct operations still in progress slowing it till finished.
Eg: if you have only just added eM Client and the server mail is still synching your accts locally, eM Client then can take time to update content depending on the size of your online mailboxes.
So when you have eM Client open outside of your Groupy dock / tab program, click the dropdown on the right of Refresh top left and click “Show Operations” and see if it’s still synching or updating anything.
There is also options within the accounts to eg: Download messages offline etc to speed up the process. So if you want to try that option let us know what account types you have.