diff --git a/ui (gen4)/features/ui.js b/ui (gen4)/features/ui.js
index bc40a622..2fbf2923 100755
--- a/ui (gen4)/features/ui.js	
+++ b/ui (gen4)/features/ui.js	
@@ -841,6 +841,7 @@ module.ViewerActions = actions.Actions({
 	flipHorizontal: [
 		function(target){ this.ribbons.flipHorizontal(target, 'view') }],
 
+	// XXX this needs an interactive mode -- mark A, mark B, align between
 	alignToRibbon: [ reloadAfter(true) ],
 
 	// tags...
diff --git a/ui (gen4)/imagegrid/data.js b/ui (gen4)/imagegrid/data.js
index dbf28b71..c3a3f315 100755
--- a/ui (gen4)/imagegrid/data.js	
+++ b/ui (gen4)/imagegrid/data.js	
@@ -2177,14 +2177,13 @@ var DataPrototype = {
 					return
 				}
 
-				if(base[set] == null){
-					base[set] = {key: base.makeSparseImages(list)}
+				var s = base[set] = base[set] || {}
 
-				} else if(base[set][key] == null){
+				if(s[key] == null){
 					base[set][key] = base.makeSparseImages(list)
 
 				} else {
-					base[set][key] = base.makeSparseImages(base[set][key].concat(list))
+					s[key] = base.makeSparseImages(s[key].concat(list))
 				}
 			})
 		})