Recently, I was building an animated tabs component for my website, something similar to the animated tab switcher found on Vercel’s dashboard (below)

animated tab

I was using Framer Motion’s layout animations to animate a background highlight that follows the active tab. Each tab was a div, and I added onMouseEnter and onMouseLeave event listeners to track which tab was currently highlighted. Simple enough, right?

It worked... until I started moving my mouse quickly between the tabs.

Sometimes, especially when I moved the mouse at a high speed, none of the tabs appeared to be hovered. The highlight vanished. It was as if my mouse had exited all the elements, even though it was clearly moving over them.

That behavior didn’t make sense.

So I dug in. And that’s when I stumbled upon the differences between onMouseEnter, onMouseOver, and onMouseMove. Not only that, I also learned that the way these events behave can vary slightly depending on the HTML element involved.

I solved the issue by replacing each div with an li. This tiny change stabilized the behavior, likely because li elements come with lighter default styles. But I’ll get to that in a minute.

onMouseEnter vs onMouseOver vs onMouseMove

At first glance, these two seem interchangeable. They both fire when your cursor enters an element. But there’s a key difference:

onMouseEnter

  • Fires only once when the pointer enters the target element.
  • Does not bubble. If a child element is hovered, it won’t trigger again.
  • Great for handling overall entry into a component.

onMouseOver

  • Fires every time the pointer enters the target element or any of its children.
  • Does bubble, which means it can fire multiple times as the cursor moves over nested elements.

onMouseMove

  • Fires every time the pointer moves within the bounds of an element.
  • Can be used for fine-grained tracking e.g., cursor position, hover animations, tooltips.

In my case, using any of the above would implement the behaviour I wanted but onMouseEnter was the most efficient since I only wanted to track when cursor enters a tab.

So... Why Did Replacing div with li Fix It?

This is where it gets interesting.

While all HTML elements can technically behave the same when styled properly, semantic HTML elements (like li, button, a, etc.) often have:

  • Fewer browser-default styles (compared to a div)
  • Simpler box models
  • Clearer accessibility and interaction expectations

In this specific case:

  • li elements are designed to be part of a list, meaning their rendering and hit-box behavior is more consistent in list-like structures.
  • The lighter layout overhead of li might make mouse transitions more predictable, reducing the chance of your cursor skipping out of bounds momentarily at high speed.

This difference isn’t always obvious, but it can have a real impact, especially when animations and fast pointer movements are involved.

How to Choose the Right Event

Use Case Recommended Event
Trigger once on entering parent onMouseEnter
Trigger on entering any child onMouseOver
Track real-time pointer motion onMouseMove

Final Thoughts

If your hover-based UI is acting flaky, especially when animations or child elements are involved, don’t immediately blame your logic. The event type and the element used can both significantly affect behavior.

Sometimes, solving bugs isn’t about changing the code, it’s about choosing the right tags and understanding what’s really going on under the hood.

If you're working with interactive elements like tabs, consider:

  • Using semantic HTML (li, button, etc.)
  • Pairing onMouseEnter with onMouseMove for better tracking
  • Avoiding deep nesting that could confuse bubbling events like onMouseOver

Thanks for reading! If you found this helpful or ran into similar quirks with mouse events, feel free to share your thoughts in the comments.