Landscape Paint Layers will not scroll to the end when using mouse wheel

In a normal detail panel, each element has its own SDetailSingleItemRow and are mostly uniformly sized with some exceptions of having a few bigger rows (i.e. asset pickers). However, these layers are all shoved into a single row which can become huge and problematic for scrolling. It seems like a lot of custom work was done here and a fix may require a total rework.

1. Have a Landscape with a material that has some number of layers (10+ can make it easy to observe).
2. Resize the Landscape Paint Mode's detail panel to where it only shows the first couple layers.
3. Scroll down the detail panel using a mouse wheel.