Alright, so I made a "responsive" toolbar. The elements on the left are pinned left (number selected) and the elements on the right are pinned right. (edit / delete) The right side tools were a DP w/ states for edit/delete and Save/Cancel, but the behavior in the GIF started happening - so I switched to show/hide on two different DPs to try to troubleshoot. It didn't fix it.
If I do not interact with the [SAVE] button on the right at all, everything works as expected. If I do, then subsequent show/hide actions on the toolbar result in shifting of it and its contents. I've been at it all day and I cannot figure out what's causing this.
It can't be the show/hide because you can show/hide with the checkboxes over and over with no drift. It's ONLY if [SAVE] is clicked that the drift starts and all the [SAVE] button does is hide the toolbar.
Latest build, Windows 10 64bit