I am having this problem with the menu system, as well.
- I click the padding value around the box element that I am trying to edit
- delete the old value by backspacing
- type in my new value
- either tab, to go to the next element, or enter, or just clicking off of the element.
Then, if I click on another item to edit and come back to the one that I just edited, the old default values for the padding are there. Not mine. I have even clicked Save after each edit, and it still doesn't work.
I hope this explanation of my process helps to you figure out the issue