Wrong Device Displaying?

As a Tableau consultant my clients have brought me many unusual behaviors, normally I can explain it away with a simple explanation of how the software works, or a quick look around a few blogs or the Tableau Forums. However, a recent issue had me spinning my wheels because none of the usual suspects were the cause, and there wasn’t even a mention of the problem in the community.

The issue:

On a dashboard being released to the first round of testers they were receiving the Tablet device view instead of the desktop view.

The twist:

This issue was only happening on some people’s computers, of a group of 20 testers it was only happening on 4 computers, and one of those was the trainer’s computer.

The obvious (but wrong) answer:

I had them check their screen resolution and all of them we significantly larger than 800 pixels tall or wide (The value that changes the display from desktop to tablet view.)

The actual solution:

The obvious answer was on the right track but not the cause of the issue. As it turns out Tableau uses the pixel size of the web browser, at the zoom level you are viewing the page at, to determine which device view you are going to receive.

I ended up creating a simple dashboard on Tableau Public that just displayed one of three text boxes based on the device type being displayed. That dashboard can be found at the following link:

http://public.tableau.com/views/DeviceTesting/Dashboard1?%3Aembed=y&%3AshowVizHome=no&%3Adisplay_count=y&%3Adisplay_static_image=y&%3AbootstrapWhenNotified=true

The following are screen shots at different levels of zoom demonstrating the issue.