Today I was trying to create a fence structure that is not higher than 1 block. I think it would be useful to add a functionality where you can declare the structure like a fence, so you can not jump over it.
Or is there may be a way to do it yet? I did not found an opportunity to create such a structure.

You can make the top part of the fence invisible. As long as its 1 block and 6 pixels tall it should be enough to not allow you to jump over.

If you are in creative you can always can use the alpha value to make parts invisible. Otherwise you can use glass or just build the fence a little higher. A player can jump 1.25 blocks high.

Thank you for the help :)