z-index reset upon scrolling start (when menu is longer than page height).

[klonos]

I've noticed this issue while trying to troubleshoot backdrop/backdrop-issues#2161...

There is a z-index of 10001 applied to the <ul> of expanded menus that go beyond the height of the page. It is applied once you hover over the parent menu and the menu is expanded. The same z-index is also applied to the scroll-up and scroll-down <span>s. Soon as there is a scroll event on the mouse though, the z-index is removed from the <ul> (still retained on the scroll <span>s):

[vadikom]

Nope, the z-index of the <ul> is only reset after it is hidden not onscroll. In your case, the style value just seems to be truncated in the dev tools view (since it's too long) but the z-index declaration is still active, you can be sure of that.

I will now check the linked issue you mentioned and see if I could be of any help...

[klonos]

Yep, double-checked and you are right that the z-index is there. Don't know what is going on then. Hmm?