These are just a few suggestions to improve the variables tab for debugging.
1. when double clicking an entry from the variables please show all the details of the selected entry in the dialog. Instead of showing just 'Value'
this could show 'Value of $currentUser/Name (String)'
2. it would even be nicer if all of the information there could be shown in a tooltip that appears on hover. That would make it even easier to quickly inspect the Name and Value of attributes.
3. Whenever you step through the debugger, all the items are collapsed again. It would be great if the collapsed/expanded state of elements could be kept. What could also help would be an option to watch certain objects / variables explicitly.
4. It would be really great if we could see the call stack during debugging!