Fixes a regression where companion window would not scroll

__tests__/src/components/CompanionWindow.test.js

@@ -105,7 +105,7 @@ describe('CompanionWindow', () => {
     companionWindow = createWrapper();
     expect(companionWindow.find(Rnd).length).toBe(1);
     expect(companionWindow.find(Rnd).prop('enableResizing').left).toBe(true);
-    expect(companionWindow.find(Rnd).prop('default')).toEqual({ height: 'auto', width: 235 });
+    expect(companionWindow.find(Rnd).prop('default')).toEqual({ height: '100%', width: 235 });
 
     companionWindow = createWrapper({ position: 'bottom' });
     expect(companionWindow.find(Rnd).length).toBe(1);

src/components/CompanionWindow.js

@@ -71,7 +71,7 @@ export class CompanionWindow extends Component {
           className={[classes.rnd]}
           style={{ display: 'flex', position: 'relative' }}
           default={{
-            height: isBottom ? 201 : 'auto',
+            height: isBottom ? 201 : '100%',
             width: isBottom ? 'auto' : 235,
           }}
           disableDragging