We show the message "You are currently editing a template and one or more pieces of connected content (wikitext and/or additional templates)." at the top of a multi-part transclusion. When I move parts around, the message starts moving around as well.
The reason is the way this is currently implemented. The message is manually inserted into the .oo-ui-stackLayout container, right next to the pages that are in this container. No widget expects an additional, unrelated element in this container. Depending on the way the new position of an element is calculated, it might naturally end at e.g. position 0, which is above the message.
