Having used a FitBit Charge2 for a year, it was the case that I never had to log back into the FitBit software on either my WIN7 PC or my Kindle Fire.
At about the same time as the Withings app had been mounted on my PC, a couple of months ago, and a link to the FitBit app established (on the PC only, AFAIK), I began to find I was being logged out of the FitBit app most days, even though I had checked the "Keep me logged in" box on logging into FitBit.
FitBit seems unable to advise.
Does anyone using Withings and FitBit have similar experience or can confirm or otherwise that the link to Withings might be causing the annoying FitBit-logouts.
I'm not bothered about losing sight of Withings data in FitBit as I only use the Withings device weekly, but maintain the FitBit 24/7.
Thanks for reading, and more for answering...