Highlight last changed element

[blochberger]

When demonstrating adding elements when there are already elements stored, it's not so easy to see which or if an element got added. It might help if the last added or updated element is highlighted (bold text).

Since elements can be deleted, this might be a bit difficult. If the latest action was to remove an element, no element should be highlighted.

This might not work well, if multiple users are using the P-Service simultaneously but should suffice for demonstration purposes.