Button to collapse all publications in the Publications panel.
Is it essential that it is a button, or could it be the behavior of collapsing the root node or a context menu option?
Should the result be the same as if you manually collapsed each Publication node? Note that if you collapse a Publication node, the expand state of all descendant nodes is kept intact, so that if you expand the Publication node again, the descendant nodes that were previously expanded are immediately expanded again.
Or do you expect typical "collapse all" functionality for a tree view, where all nodes are collapsed?
Button to collapse all publications in the Publications panel.