Fix selectionMode none dragging (#3696)

* Fix selectionMode none dragging and allow for the scrolling region to be different

Author: snowystinger

packages/@react-aria/selection/src/useSelectableCollection.ts

@@ -370,7 +370,7 @@ export function useSelectableCollection(options: AriaSelectableCollectionOptions
     onBlur,
     onMouseDown(e) {
       // Ignore events that bubbled through portals.
-      if (e.currentTarget.contains(e.target)) {
+      if (scrollRef.current === e.target) {
         // Prevent focus going to the collection when clicking on the scrollbar.
         e.preventDefault();
       }

packages/@react-spectrum/list/stories/ListView.stories.tsx

@@ -378,6 +378,14 @@ storiesOf('ListView/Drag and Drop', module)
       </Flex>
     )
   )
+  .add(
+    'Drag within list scrolling (Reorder)',
+    args => (
+      <Flex direction="row" wrap alignItems="center" height={100}>
+        <ReorderExample {...args} disabledKeys={['1']} onDrop={action('drop')} onDragStart={action('dragStart')} onDragEnd={action('dragEnd')} />
+      </Flex>
+    )
+  )
   .add(
     'Drag into folder',
     args => (
@@ -802,6 +810,7 @@ export function ReorderExample(props) {
       aria-label="reorderable list view"
       selectionMode="multiple"
       width="300px"
+      height="100%"
       items={list.items}
       disabledKeys={disabledKeys}
       dragAndDropHooks={dragAndDropHooks}