I want to provide alignment features to my diagram. Users would select multiple items, and align them to the center, left, right, etc, against the "focused" item in the selection: the item with the contrasting selection handles.

I couldn't find how to determine which selected node is this "focused" node. The selection handles are drawn white, while the rest of the selected nodes have gray handles.

Is there a way to figure out which selected node is the focused one?