URL: https://www.codecademy.com/en/courses/learn-java/lessons/introduction-to-java/exercises/whats-your-name
Browser / Version: Firefox 49.0
Operating System: Linux
Problem type: Something else - I'll add details below

Steps to Reproduce

1. Navigate to: https://www.codecademy.com/en/courses/learn-java/lessons/introduction-to-java/exercises/whats-your-name
2. Once the site load, try to adjust the mini-window(s) positions by moving it left or right using the dividers that separate them.

Expected Behavior:
Smooth movement while adjusting the mini window sizes

Actual Behavior:
Lots of jank while movement of the dividers

Note: You'll have to log in to this site.
Im not fully sure but i feel the site kind of lags on Firefox

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