diff --git a/ui/TODO.otl b/ui/TODO.otl
index 09e1947a..03b391c2 100755
--- a/ui/TODO.otl
+++ b/ui/TODO.otl
@@ -110,6 +110,13 @@ Roadmap
 
 [_] 28% Gen 3 current todo
 	[_] 56% High priority
+		[_] BUG: appear to be leaking memory on very large sets of images (>8K)
+		| don't remember it before, so it might be due to the new 
+		| loadImagesAround(..)
+		|
+		| Another place to check is pre-caching...
+		|
+		| Ran a test session -- we appear to never invalidate cache...
 		[_] 66% Bookmarks
 			[X] toggle
 			[X] save/load
diff --git a/ui/tags.js b/ui/tags.js
index 64484418..b463b9d4 100755
--- a/ui/tags.js
+++ b/ui/tags.js
@@ -299,10 +299,15 @@ function setupTags(viewer){
 	viewer
 		.on('imagesLoaded', function(){
 			TAGS = []
-			showStatusQ('Tags: building index...')
+
+			showStatusQ('Tags: Index: building...')
+
 			// XXX should this be sync???
+			var t0 = Date.now()
 			buildTagsFromImages()
-			showStatusQ('Tags: building index: done.')
+			var t1 = Date.now()
+
+			showStatusQ('Tags: Index: done ('+( t1 - t0 )+'ms).')
 		})
 
 }