If you have a chromium-based browser you can find out what events are affecting a particular item on you web-page using the monitorEvents function.
Inspect The Element
First right-click on the element that you are interested in and pick "Inspect element" from the context-menu.
Enter the Event Type
$0 is a variable that refers to the element you are inspecting and "mouse" tells it to listen for mouse events
Now, as you do things with your mouse on the element, the console output will show you the the events as they happen.
Listing Event Listeners
To see the event-listeners associated with the element enter the following at the console.
The getEventListeners function doesn't work until you've run the monitorEvents function.