When I open Firefox, I immediately am met with a popup asking for my primary password.
Please do not show this password dialog box until I am actually trying to log in to a website. In other words, don't show it when I first open the browser. Only show it when I go to a page with a password field on it (It already does this so really just need to remove the prompt at startup.)
I was very confused by this when I fist started using Firefox's password manager because it wasn't clear where the dialog came from or why. It was so confusing and jarring that it nearly made me stop using the password manager after I first set it up. It continues to annoy me.
I also think that the dialog box should have a reference to the tab that prompted it. For example, the tab title should be included in the dialog box. That way it is clear that the popup dialog is associated with the needs of a specific tab.
I think that Firefox won't sync with Firefox sync until the primary password is entered. I think that may be why it appears when Firefox is first opened. I wish that the primary password is only needed to use saved passwords.
I think that Firefox won't sync with Firefox sync until the primary password is entered
This is correct, but I still think this is a good idea. It should be a user preference. If it is set to not prompt for Primary Password until needed, then the first time the user enters it to autofill a password field, THEN Firefox Sync will start syncing. If the user wants to make it sync without autofilling anything, they can still click the "tabs from other devices" bookmark button to force a sync and prompt for the Primary PW.