Did you check the inner and outer padding of each of your containers? Any chance you could upload a sample workbook?
Attached an example, in 10.5 the vertical container (shaded yellow) would collapse down to 1px like the other sheets but now it seems stuck at 30px even when there is nothing inside it.
I don't fully understand the issue but it does look like the container is reserving a minimum space for itself inside the dashboard canvas. The reason I don't fully understand the issue is because I've never had a requirement to put an empty layout container onto a viz (or a container that needed to be smaller than 30 pixels).
Thanks for looking at it,
The issue is that on views 1,2,3 I've permanently lost a full height 30px wide column on my dashboards, I highlighted it in yellow. The container is not empty, it has view #4 inside it which is 2 sheets in a vertical container.
All other sheets collapse down to 1px while the vertical one stays at 30 even though there is nothing visible inside while on view 1 2 or 3.
When on view 4 you can see it takes the will width of the main container and does not have any wasted space.
This worked in 10.5, after the 2018 update every dashboard I have with a vertical container sheet switcher has a messed up layout.
Thanks for the further explanation. I took a fresh look at the viz and rearranged it so that the blank bar does not show by nesting sheets 1-3 inside the same layout container as 4.1 and 4.2.
HTH 18.1 attached
Thanks for taking another look, that fixed my original problem although it introduces another.
With vertical containers the sheets do not collapse onto themselves in the same position so every 1px vertical sheet adds on top of each other. The more sheets that are added in a vertical the more things will unintentionally move around. It's even noticeable in the 4 sheet example in your reply.
I believe I narrowed the problem down to the fit height/width options. Horizontal containers will only take up a single 1px column even with 100 of sheets in it when all the sheets are set to fit width - works with long lists
In vertical containers with fit width they will not stack on top of each other so each view adds a 1px shift. This adds up quickly with many sheets on a dashboard. If the vertical container is set to fit height they will stack on top of each other just like the horizontal ones, but that is not practical if you are displaying list data or anything that will not fit on one page.