Clear Async options after making a selection

Currently, when you make a selection from an async
dropdown, it keeps the list open but clears the input.

This looks inconsistent and doesn't match the common UX
for async search (looking up an item from a long list).

src/Async.js

@@ -72,6 +72,10 @@ export default class Async extends Component {
 		});
 	}
 
+	clearOptions() {
+		this.setState({ options: [] });
+	}
+
 	loadOptions (inputValue) {
 		const { cache, loadOptions } = this.props;
 
@@ -174,7 +178,13 @@ export default class Async extends Component {
 			noResultsText: this.noResultsText(),
 			placeholder: isLoading ? loadingPlaceholder : placeholder,
 			options: (isLoading && loadingPlaceholder) ? [] : options,
-			ref: (ref) => (this.select = ref)
+			ref: (ref) => (this.select = ref),
+			onChange: (newValues) => {
+				if (this.props.value && (newValues.length > this.props.value.length)) {
+					this.clearOptions();
+				}
+				this.props.onChange(newValues);
+			}
 		};
 
 		return children({