Hello,
Since the Number of Items in the Menu are more than the Available Area it is important to adjust the Padding and Font Size to make the Menu on a Single Line. We Really Apologize but we could not check the Video. Can you host it somewhere else and provide us with a Link so that we can check the exact issue with this.
Additionally, it would also be helpful if you could please let us know which Browser and OS you are using currently so that we can investigate this issue further. Thanks for your Patience.
Meanwhile, do let us know if we can help you with anything else or if you find any further issues with Canvas.