Using NS w/BU - although I have BU disabled and bought iDrive, but that is another story - on Windows 8.1 Pro 64 Bit
[Top is the IS Toolbar, bottom is the actual Favorites Bar]
Often times, as IS tries to find the proper log-in, it replicates my IE 11 Favorites Bar, stutters a bit, before returning to itself, visually, and finally filling the form or log-in. Very annoying, to say the least.
I hope this is addressed - at least before the Windows 10 release!