Multiselection - avoid calling onChange if the value if the changes a…

…re synced with the value prop (#2324)

lib/MultiSelection/MultiSelection.js

@@ -166,7 +166,12 @@ const MultiSelection = ({
                                   boil each object down to a string, so that the strict-equals will
                                   have a better time succeeding.  */
     onSelectedItemsChange(changes) {
-      onChange(changes.selectedItems);
+      // only trigger onChange if selectedItems is different from from the incoming value prop.
+      // this avoids instances when the value can appear *not to change for the user but it's really the cause of
+      // values just changing between re-renders and react just catching whichever onChange was triggered last.
+      if (!isEqual(value, changes.selectedItems)) {
+        onChange(changes.selectedItems);
+      }
       awaitingChange.current = false;
     },
     onStateChange({ selectedItems: newSelectedItems, type }) {
@@ -422,7 +427,7 @@ const MultiSelection = ({
       getInputProps={getInputProps}
       getDropdownProps={getDropdownProps}
       isOpen={isOpen}
-      placeholder={selectedItems.length === 0 && placeholder}
+      placeholder={selectedItems.length === 0 ? placeholder : ''}
       menuId={menuId}
       setFilterValue={setFilterValue}
       setFilterFocus={setFilterFocused}