I had two browser windows grouped with Groupy on my Windows 10 desktop PC.
Then I started a Remote Desktop connection to my desktop PC from my MS Surface Pro 4 laptop.
When I killed the Remote Desktop session and returned to my Windows 10 desktop PC, the Groupy tab bar had bloated to many times its proper size. I tried ungrouping and regrouping the browser windows and turning off Groupy and turning it on again, but the massive tab bar persisted.
I suspect the problem is due to the laptop having a different resolution to the desktop, but other apps seem to cope with the switch without such problems.
