how to scroll the element belong to a group? Options

[ericsia]

It is too hard to describe as word, here is what I mean:
https://jsbin.com/kalodos/edit?html,css,output

[ericsia]

user will scroll using mouse wheel most likely

[pandy]

I don't understand. When I hold the pointer over the square it changes colour and I can scroll the lines with the mouse wheel. What's the problem?

[Christian J]

I don't understand. When I hold the pointer over the square it changes colour and I can scroll the lines with the mouse wheel.

I can't do that, not even in K-Meleon. Are you sure it's not the viewport scrollbar you see moving?

[ericsia]

I don't understand. When I hold the pointer over the square it changes colour and I can scroll the lines with the mouse wheel.

I can't do that, not even in K-Meleon. Are you sure it's not the viewport scrollbar you see moving?

I can't scroll it either. I want the inner items (onesssss) to scroll when the mouse is on the square.
Owh btw, I'm looking for a pure css solution.

[pandy]

But they do scroll. I.e. the page scrolls but the fixed box stays put. What browser do you use?

[Christian J]

I want the inner items (onesssss) to scroll when the mouse is on the square.

Yes that's what I meant too, the DIV with "overflow: auto". But do you really need nested scrollable sections like that on the page? It might be difficult to use even if it worked.

But the do scroll. I.e. the page scrolls but the fixed box stays put.

I can scroll the page too, but occasionally even that it stops working (at least in Vivaldi). Not sure why, maybe it's a bug.

[ericsia]

I want the inner items (onesssss) to scroll when the mouse is on the square.

Yes that's what I meant too, the DIV with "overflow: auto". But do you really need nested scrollable sections like that on the page? It might be difficult to use even if it worked.

Yes I need that, the blue box was meant to be a message box with transparent background, but I added color to help us see the region