How should the diagram + execution details be arranged?
Diagram on top, tabbed detail panel below. Resizable splitter between them. Maximizes diagram width. Tabs: Input, Output, Headers, Error, Timeline.
Diagram on left, collapsible detail panel on right. Slide-in when node selected. Diagram keeps full height.
Diagram on top, bottom split into processor list (left) + detail tabs (right). Clicking processor in list or diagram syncs selection. Most information density.