Ah! it takes some time for that to pop up. It is now clear what this does. That said is storing the password in memory safe or does it open up a hole for someone to exploit? Should you ask for the short password as per the GRC App? I appreciate that means more things to set up and manage.Do you mean the help text when you hover over the "Password" text is not clear?
I think the "........." underline perhaps needs a mention in the help text that anything underlined as such will pop up a tool tip.
FF V67.0.4/64, (See my Sig)Which version of Firefox are you running?
They fixed the blank popup very recently.
I think I have a way to re-create the issue, when you need to click the SQRL Icon in the toolbar, with the left mouse button on the icon hold it down for a "long" click just to exaggerate try 2 or 3 seconds, i think you will get a blank box every time. This works for either the main screen or a password input.