Can be reproduced on - 5.0, 6.0, 6.4, master.

Steps to reproduce:
1) Create item with name - <img src="x" onerror="alert('UWAGA');"/>
2) Create graph and add created item to items list.
3) Save graph.
4) Open created graph again and click on added item.

5) Then click on its name.

Result:

Expected:
No alarm message.