=== modified file 'dhis-2/dhis-web/dhis-web-commons-resources/src/main/webapp/dhis-web-commons/ouwt/ouwt.js'
--- dhis-2/dhis-web/dhis-web-commons-resources/src/main/webapp/dhis-web-commons/ouwt/ouwt.js	2015-03-30 16:22:29 +0000
+++ dhis-2/dhis-web/dhis-web-commons-resources/src/main/webapp/dhis-web-commons/ouwt/ouwt.js	2015-04-08 09:55:13 +0000
@@ -745,7 +745,7 @@
     };
 
     var expandTreeAtOrgUnit = function( ou, select ) {
-        select = select || false;
+      select = select || false;
 
       if( organisationUnits[ou] == null ) {
           subtree.ajaxGetLeaf(ou).done(function( data ) {
@@ -851,6 +851,7 @@
             var def = $.Deferred();
 
             subtree.ajaxGetChildren( parentId ).done(function( data ) {
+                $('#orgUnitTree').trigger('dhis2.ouwt.childrenLoaded', parentId);
                 def.resolveWith( window, [ data ] );
             });
 

=== modified file 'dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js'
--- dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js	2015-03-27 14:46:32 +0000
+++ dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js	2015-04-08 09:55:13 +0000
@@ -74,6 +74,9 @@
 // Indicates whether current form is multi org unit
 dhis2.de.multiOrganisationUnit = false;
 
+// List of parent for which we have fetched dataSet associations, used to optimize dhis2.de.fetchDataSets
+dhis2.de.fetchedChildren = [];
+
 // "organisationUnits" object inherited from ouwt.js
 
 // Constants
@@ -222,6 +225,12 @@
         $.when( dhis2.de.getMultiOrgUnitSetting(), dhis2.de.loadMetaData(), dhis2.de.loadDataSetAssociations() ).done( function() {
         	dhis2.de.setMetaDataLoaded();
         	organisationUnitSelected( ids, names );
+
+          $('#orgUnitTree').on('dhis2.ouwt.childrenLoaded', function(e, ou) {
+            dhis2.de.fetchDataSets(ou).done(function() {
+                selection.responseReceived();
+            })
+          });
         } );
     } );
 } );
@@ -980,21 +989,26 @@
 {
     var def = $.Deferred();
 
-    $.ajax({
-        type: 'GET',
-        url: '../api/organisationUnits/' + ou,
-        data: {
-            fields: 'id,dataSets[id],children[id,dataSets[id]]'
-        }
-    }).done(function(data) {
-        dhis2.de._updateDataSets(data);
-
-        data.children.forEach(function( item ) {
-            dhis2.de._updateDataSets(item);
+    if( dhis2.de.fetchedChildren.indexOf(ou) != -1 ) {
+        def.resolve();
+    } else {
+        $.ajax({
+            type: 'GET',
+            url: '../api/organisationUnits/' + ou,
+            data: {
+                fields: 'id,dataSets[id],children[id,dataSets[id]]'
+            }
+        }).done(function(data) {
+            dhis2.de._updateDataSets(data);
+
+            data.children.forEach(function( item ) {
+                dhis2.de._updateDataSets(item);
+            });
+
+            dhis2.de.fetchedChildren.push(ou);
+            def.resolve(data);
         });
-
-        def.resolve(data);
-    });
+    }
 
     return def.promise();
 };