Listbox scrollbar thumb changes size when content is variable height

Question

I have a ListBox with many objects displayed, each of which can be a variable height, based on the number of values each object has. See my previous question that was answer

Answer 1

Set ScrollViewer.CanContentScroll="False" on the ListBox, this will disable what's called "logical scrolling", which does scrolling based on item count instead of height ("physical scrolling").