Rerender views if necessary when scrolling horizontally

If the context says it wants to rerender when its width changes, we must also
rerender when the horizontal scroll position changes.

pkg/gui/controllers/list_controller.go

@@ -74,6 +74,9 @@ func (self *ListController) scrollHorizontal(scrollFunc func()) error {
 	scrollFunc()
 
 	self.context.HandleFocus(types.OnFocusOpts{})
+	if self.context.NeedsRerenderOnWidthChange() == types.NEEDS_RERENDER_ON_WIDTH_CHANGE_WHEN_WIDTH_CHANGES {
+		self.context.HandleRender()
+	}
 	return nil
 }