Use Popup.back() instead of Popup.close() to get no conflicts if a Popup is opened as "Sub Popup"

- .back() is also .close() if there is no "popup layer" left

client/components/swimlanes/swimlaneHeader.js

@@ -39,7 +39,7 @@ Template.swimlaneActionPopup.events({
   'click .js-close-swimlane'(event) {
     event.preventDefault();
     this.archive();
-    Popup.close();
+    Popup.back();
   },
   'click .js-move-swimlane': Popup.open('moveSwimlane'),
   'click .js-copy-swimlane': Popup.open('copySwimlane'),
@@ -88,7 +88,7 @@ BlazeComponent.extendComponent({
           // XXX ideally, we should move the popup to the newly
           // created swimlane so a user can add more than one swimlane
           // with a minimum of interactions
-          Popup.close();
+          Popup.back();
         },
         'click .js-swimlane-template': Popup.open('searchElement'),
       },
@@ -118,11 +118,11 @@ BlazeComponent.extendComponent({
         },
         'click .js-submit'() {
           this.currentSwimlane.setColor(this.currentColor.get());
-          Popup.close();
+          Popup.back();
         },
         'click .js-remove-color'() {
           this.currentSwimlane.setColor(null);
-          Popup.close();
+          Popup.back();
         },
       },
     ];