Monitoring graph cursor flag should not be "in front" of the hover calculation
The graph "cursor flag" blocks the hover position calculation for the graph behind it, so if you scroll too fast to the right, you'll often accidentally hover over the date/time text and the graph position will no longer update to follow your cursor until you move it off of the flag.
This could be fixed by putting the flag behind whatever overlay element is being used to capture the mouse position. Probably as simple as changing a z-index
value or two.
Edited by Mike Greiling