added customized file for debugging
minor change in commenting style
re-enabled titleCollapse
See description.

Now the scrolling is restricted to the appropriate range, so is panning.
Hovering alters the border color of a node (only for step nodes at the
moment).
Expanding a panel highlights the corresponding node.
Hovering on the parameter panel header highlights the corresponding
node with the hovering color.
Positioning of the label is changed to fit the hovering style.