Feature request: alter Thunderbird's *window* if there are unread messages in configured folders

[gkresic]

Description: add another notification method which will alter Thunderbird's window for as long as there are unread messages in configured folders. Alteration should be "strong" in a way you could see it even from far away. Few ideas, as I don't know what is technically possible:

• change window background (what if there are multiple Thunderbird windows opened?)
• change background of custom toolbar (Mailbox Alert currently doesn't have one, but it may have)

This notification method would complement current methods which are ephemeral and easy to miss if you are not in front of your computer when messages arrive.

[kupietools]

What would be fantastic is to have it open a mailbox in a new window if new emails come in to that box and it's not already open in a window.

I do have this implemented using js filters in filtaquilla and folder listeners, but it's extremely complicated & fragile and it would be nice to have a plugin that just does it.