Fixed flickering when inserting properties from library by ensuring consistent ID generation

app/imports/api/creature/creatureProperties/methods/insertPropertyFromLibraryNode.js

@@ -59,8 +59,10 @@ const insertPropertyFromLibraryNode = new ValidatedMethod({
 			'ancestors.id': nodeId,
 			removed: {$ne: true},
 		}).fetch();
-    // The root node is last in the array of nodes
-		nodes.push(node);
+
+    // The root node is first in the array of nodes
+    // It must get the first generated ID to prevent flickering
+		nodes = [node, ...nodes];
 
 		// re-map all the ancestors
 		setLineageOfDocs({
@@ -82,10 +84,10 @@ const insertPropertyFromLibraryNode = new ValidatedMethod({
 		});
 
 		// Insert the creature properties
-    let insertedDocIds = CreatureProperties.batchInsert(nodes);
+    CreatureProperties.batchInsert(nodes);
 
     // get the root inserted doc
-    let rootId = insertedDocIds[insertedDocIds.length - 1];
+    let rootId = node._id;
 
     // Tree structure changed by inserts, reorder the tree
     reorderDocs({
@@ -97,7 +99,6 @@ const insertPropertyFromLibraryNode = new ValidatedMethod({
     recomputeInactiveProperties(rootId);
 		// Inserting a creature property invalidates dependencies: full recompute
     recomputeCreatureByDoc(rootCreature);
-
 		// Return the docId of the last property, the inserted root property
 		return rootId;
 	},

app/imports/api/parenting/parenting.js

@@ -120,13 +120,19 @@ export function setLineageOfDocs({docArray, oldParent, newAncestry}){
 export function renewDocIds({docArray, collectionMap}){
   // map of {oldId: newId}
   let idMap = {};
-  // Give new ids and map the changes
+
+  // Get a random generator that's consistent on client and server
+  let randomSrc = DDP.randomStream('renewDocIds');
+
+  // Give new ids and map the changes as {oldId: newId}
   docArray.forEach(doc => {
     let oldId = doc._id;
-    let newId = Random.id();
+    let newId = randomSrc.id();
     doc._id = newId;
     idMap[oldId] = newId;
   });
+
+  // Remap all references using the new IDs
   const remapReference = ref => {
     if (idMap[ref.id]){
       ref.id = idMap[ref.id];