There are 3 scrolls: window, div with blue boxes, div with green boxes. Contenteditable div is on very bottom level.
Flex Box Element 1
Flex Box Element 3
Top Form field 1
Second top Menu
Second scrollable form content 1
Second scrollable form content 2
Second scrollable form content 3
Sticky positioned tool bar, higher zIndex
Sticky positioned tool bar, same zIndex
Second scrollable form content 2
Second scrollable form content 3
Second scrollable form content 4
Second scrollable form content 5
Top Form field 2
Top Form field 3
Top Form field 4
Menu, Absolutely positioned.
Looong Div for window scroll