This is about Angular Material Sidenav component. In the code below, when I increase the border radius so that it overlaps the enclosing element, the element disappears.

  Drawer content 
  Main content 

(Content is visible when there is no border radius)

(The content disappears after adding the border radius)

Stackblitz: https://stackblitz.com/edit/7swnhp?file=src/example/sidenav-drawer-overview-example.html

I can't see where the element goes, I can't see any hidden styles being applied, in the DOM I can see it's there but it's not visible.