With Version 1511 of Windows 10 (build 10586, codename TH2 or Threshold 2), we released a few improvements and fixes to Adaptive Tile Templates. And now, the Notifications Visualizer app has been updated (version 184.108.40.206) to reflect the changes in the new OS update!
Instantly flip between Version 1511 and Windows 10 RTM
Using the Visualizer, you can compare how your tile looks on the latest Version 1511 update and the original Windows 10 RTM version. This is helpful if you want to use some new adaptive features that we added, but still want to understand how your tile will look for users who haven't updated yet.
To change builds, go to the "Settings" page and notice the new "OS build number" option. You can select from build 10586 (Version 1511) or 10240 (RTM).
You will get full error/warning reporting and instant visual previews for each of the two builds of Windows. For example, in RTM, peek images did not support circle cropping. When you have 10240 selected, you'll get a warning telling you that it's not supported, and the normal square peek image will be displayed. When you have 10586 selected, there's no warning and the peek displays as a circle.