None of the Viewport presets work for me on Chromium 46 in Debian sid on the Cinnamon desktop, and also at home on a similar system with LXDE. Whenever I select a Viewport preset, it always reports:
Viewport resizing doesn't work on special browser pages, such as the "New tab", "Downloads", "Settings" pages and so on.
If this is not the case, please reload the page and try again.
However, no tabs are open to special browser pages. The problem is reproducible with a single tab open to the site I'm developing.
I've had to change them all to Window for now, but that's inaccurate for the platforms they're supposed to represent.
For comparison, I tested on my Windows 7 VM with Chrome 46.0.2490.80 on Virtualbox. The Viewport presets work fine there.
Customer support service by UserEcho