Web UI bouncing dropdown config boxes

[is8ac]

To reproduce:
Go to the web GUI http://localhost:9443/www/dashboard#/ Click on the hamburger menu. Click on config. Click on any one of the sub menus. When you click on a +, the relevant text box drops down with an animation, and stays dropped down. This is good and correct
Now go to hamburger > config > any other config bubble. Click on a +.

Expected behavior: The text box drops down and stays dropped down.

Observed behaviour: The text box drops down and immediately retracts, preventing its use.

The expanding text boxes in the web UI move n times, where n is the number of config pages which you have previously opened since last reloading the page. If n is not evenly divisible by 2, then it ends up exposed and usable. If n is divisible by 2, then it ends up retracted and is unusable.