I am using two brand new fire 8 tablets as wall panels. Both are running the fully kiosk app. On the first tablet, when in full screen my HA dashboard shows three columns of buttons and this fits perfectly my needs, as there is no need to scroll down to see every button on the page.
Viewing the same dashboard on the second tablet in full screen there are only two columns of buttons, therefore I need to scroll down to see every button.
I cannot get the second tablet to display three columns. I guess the problem is not with HA but with the tablet settigs? but I cannot figure out why both identical tablets do not display the dashboard in the same way.
Fully Kiosk has a lot of settings. First thing if you haven’t done it already might be to check that they are all the same on both tablets.
You might also try creating a test page which forces the dashboard to display the buttons in three colums - left to their own devices HA dashboards can be a bit unpredictable. One way to do this is to create a vertical stack with each row containing a horizontal stack of three cards. If this appears the same on both tablets you can probably take it that the original dashboard itself was playing tricks.
Thank you both for your suggestions. What I forgot to mention is that a third tsblet, an iPad mini, clearly demonstrates the erratic behavior of HA: When I load the very same dashboard on my iPad, sometimes it displays three rows, sometimes only two. I will try stacking my cards as suggested, thank you.
