nested confine areas

i formulating control wpf, i have doubt wpf gurus out there.

i wish control means enhance fit resizable window.

in control, i have list box i wish enhance window. i also have controls around list box (buttons, text, etc).

i wish means set smallest distance control, nonetheless i wish window means sized smaller formulating confine bars regard control.

this creates nested confine areas: list box scrollviewer jacket whole control.

now, list box set automobile size, never have confine bar since always drawn full distance within scrollviewer.

i wholly wish control confine calm can't any smaller, differently i don't wish confine control; instead i wish confine list box inside control.

how i change default function scrollviewer class? i attempted inheriting scrollviewer category vital measureoverride arrangeoverride classes, nonetheless i couldn't figure out magnitude arrange child properly. appears arrange impact scrollcontentpresenter somehow, tangible calm child.

any help/suggestions many appreciated.