When a lot of apps are open in Windows, things can become a bit confusing. A tool like Groupy can help with that.
When it is active, you can (as the name implies) group apps together, so you can keep them in one place and switch in between them through tabs (even comes with a mouse over preview). Windows 10 is going to have a similar feature called “Sets” in the future, but that is going to be limited to UWP applications, Groupy can be used with pretty much every app.
After several weeks of use, for me Groupy has been absolutely stable and I can recommend it. On its own it costs 9.99$ over on Stardocks’ website ( https://www.stardock.com/products/groupy/ ). It’s also part of the Stardock Object Desktop package which contains several other handy tools (29.99$ currently).