By default zoho mail has an avatar with the email initials on a colored background.

But the background randomly changes for each email in a thread regardless of the email address from which it came, making multi-email conversations hard to follow.

For example, these 3 emails in a thread are coming from the same email address, but the avatars are colored as if they are coming from different accounts.

And the colors don't even persist through reloads (same thread after a reload)

Is there a way to make a color "stick" to a email address? Or easily assign an avatar to it?