""...Slack and Evernote are UWP apps in the Windows 10 Store but for desktop only, so after you dock your phone they don't open on your main display: the phone versions aren't multimode."
Seriously?"
Yes, seriously, if the developers dont develop the apps to allow multi mode then they wont work on multi mode environments - I dont see that as a failing of the OS. That said MS really should have pushed continuum more than it did/does - it is one of the features that would really make me willing to pay more for a phone - to the extent that Im considering the s8 now having made do with an HTC One for the last 4 years.
Biting the hand that feeds IT
