Interactive Dependency Editing

Draw: hover any bar — two blue circles appear at its start/finish edges. Drag from a circle onto another bar to create a dependency; the (source-anchor, target-anchor) pair picks the type (FS / SS / FF / SF).
Delete: hover an arrow → it darkens; click → it turns red with a ✕ at the head; click the ✕, press Delete, or hit Backspace to remove. Esc cancels a drag or clears selection.
Every change is undoable with Ctrl/Cmd + Z.

Try it:

Hover Design — drag from its right-edge circle onto another bar's left edge → creates an FS edge
Drag from left-edge to left-edge → SS; right-edge to right-edge → FF; left-edge to right-edge → SF
Try dragging from Launch back to Design — the preview turns red (cycle)
Click any existing arrow then the red ✕ to remove it
Press Ctrl/Cmd + Z to undo