diff --git a/src/ui-layout.js b/src/ui-layout.js
index 41253c8..41818fb 100644
--- a/src/ui-layout.js
+++ b/src/ui-layout.js
@@ -525,7 +525,7 @@ angular.module('ui.layout', [])
           if(prevContainer) {
             prevContainer.size += (c.uncollapsedSize + endDiff);
           }
-
+          prevContainer.uncollapsedSize = null;
         } else {
           c.size = c.uncollapsedSize;