From time to time, gnome-shell presents me with a modal dialogue asking me for a password for some online ressource. 

It does not say which one it is, as the only hint it reveals is an associated e-mail address, but since my e-mail address is associated with multiple online accounts (e.g. imap, owncloud, google, facebook), this is complete guesswork. 

Also, gnome-shell does not reveal, which application is asking for my password. I have no idea, why and to whom I am giving my credentials. This could even be a security issue, because it could just as well be some malicious application. Given the lack of information provided by the prompt, I have no way of knowing what is going on.

Lastly, since I use securing unique passwords for each account, I store them in a password manager. Since the modal dialogue blocks everything, there is no way of bringing up the password manager and copying the password, other than cancelling the password prompt. But once I've done that, there is no way of brining it back.

I supposed this design was well-intentioned, but for all practical purposes, it is brain-dead and drives me nuts! So I'd suggest to refrain from using a blocking modal dialogue for passwords for remote accounts and also provide more complete information about which application is requesting the password for which account.