Problem with fixed widget

Hi, I have a problem. Depending on settings, fixed widget either doesn’t work, or breaks my website. I’ll explain and show it in details:

Before last update, I had #footer as my stop element. Everything worked fine: fixed element stoped right before reaching footer. And now here is what happens:

1 – If I turn on checkbox “test new version”, and put #footer in both “custom fixed elements” and “stop elements” fields, then my footer jumps to the top of page: https://ibb.co/mch0419 . I know, that selector has to be added only in one field, but I wanted to test everything.

2 – If I turn on checkbox “test new version”, and put #footer only in “custom fixed elements” field, then needed element in sidebar doesn’t get fixed, and my footer just disappears: https://ibb.co/tBFZSNv

3 – If I turn on checkbox “test new version”, and put #footer only in “stop elements” field, then footer doesn’t disappear, but needed element doesn’t get fixed: https://ibb.co/qB5C6jH

4 – If I turn off checkbox “test new version”, and put #footer in both “custom fixed elements” and “stop elements” fields, then needed element gets fixed, but goes through my footer: https://ibb.co/1JRSf4s

5 – If I turn off checkbox “test new version”, and put #footer only in “custom fixed elements” field, then the same problem happens, as in previous example.

6 – If I turn off checkbox “test new version”, and put #footer only in “stop elements” field, then footer doens’t disappear / doesn’t get broken, and needed element get fixed. However, it stops long before reaching footer, even though there is no margin bottom put in your plugin’s settings: https://ibb.co/12SWsjM

I hope, that I’ve explained everything well!

The page I need help with: [log in to see the link]