diff --git a/modules/core/validator.js b/modules/core/validator.js
index 0f8a3a1c8..ac04e92a3 100644
--- a/modules/core/validator.js
+++ b/modules/core/validator.js
@@ -488,10 +488,10 @@ export function coreValidator(context) {
     _headCache.graph = currGraph;  // take snapshot
     _completeDiff = context.history().difference().complete();
     const incrementalDiff = coreDifference(prevGraph, currGraph);
-    const entityIDs = Object.keys(incrementalDiff.complete());
+    let entityIDs = Object.keys(incrementalDiff.complete());
+    entityIDs = _headCache.withAllRelatedEntities(entityIDs);  // expand set
 
-    // if (!entityIDs.size) {
-    if (!entityIDs.length) {
+    if (!entityIDs.size) {
       dispatch.call('validated');
       return Promise.resolve();
     }
@@ -540,8 +540,8 @@ export function coreValidator(context) {
       if (!_headCache.graph) _headCache.graph = baseGraph;
       if (!_baseCache.graph) _baseCache.graph = baseGraph;
 
-      const entityIDs = entities.map(entity => entity.id);
-      // entityIDs = entityIDsToValidate(entityIDs, baseGraph);  // expand set
+      let entityIDs = entities.map(entity => entity.id);
+      entityIDs = _baseCache.withAllRelatedEntities(entityIDs);  // expand set
       validateEntitiesAsync(entityIDs, _baseCache);
     });
 
@@ -629,7 +629,7 @@ export function coreValidator(context) {
   // - the user did something to one of the entities involved in the issue
   //
   // Arguments
-  //   `entityIDs` - Array containing entity IDs.
+  //   `entityIDs` - Array or Set containing entity IDs.
   //
   function updateResolvedIssues(entityIDs) {
     entityIDs.forEach(entityID => {
@@ -656,7 +656,7 @@ export function coreValidator(context) {
   // Schedule validation for many entities.
   //
   // Arguments
-  //   `entityIDs` - Array containing entity IDs.
+  //   `entityIDs` - Array or Set containing entityIDs.
   //   `graph` - the graph to validate that contains those entities
   //   `cache` - the cache to store results in (_headCache or _baseCache)
   //
@@ -666,7 +666,7 @@ export function coreValidator(context) {
   //
   function validateEntitiesAsync(entityIDs, cache) {
     // Enqueue the work
-    const jobs = entityIDs.map(entityID => {
+    const jobs = Array.from(entityIDs).map(entityID => {
       if (cache.queuedEntityIDs.has(entityID)) return null;  // queued already
       cache.queuedEntityIDs.add(entityID);
 
@@ -795,24 +795,20 @@ function validationCache(which) {
     issuesByEntityID: {}  // entity.id -> Set(issue.id)
   };
 
-  cache.cacheIssues = (issues) => {
-    issues.forEach(issue => {
-      const entityIDs = issue.entityIds || [];
-      entityIDs.forEach(entityID => {
-        if (!cache.issuesByEntityID[entityID]) {
-          cache.issuesByEntityID[entityID] = new Set();
-        }
-        cache.issuesByEntityID[entityID].add(issue.id);
-      });
-      cache.issuesByIssueID[issue.id] = issue;
+
+  cache.cacheIssue = (issue) => {
+    (issue.entityIds || []).forEach(entityID => {
+      if (!cache.issuesByEntityID[entityID]) {
+        cache.issuesByEntityID[entityID] = new Set();
+      }
+      cache.issuesByEntityID[entityID].add(issue.id);
     });
+    cache.issuesByIssueID[issue.id] = issue;
   };
 
+
   cache.uncacheIssue = (issue) => {
-    // When multiple entities are involved (e.g. crossing_ways),
-    // remove this issue from the other entity caches too..
-    const entityIDs = issue.entityIds || [];
-    entityIDs.forEach(entityID => {
+    (issue.entityIds || []).forEach(entityID => {
       if (cache.issuesByEntityID[entityID]) {
         cache.issuesByEntityID[entityID].delete(issue.id);
       }
@@ -820,25 +816,33 @@ function validationCache(which) {
     delete cache.issuesByIssueID[issue.id];
   };
 
+
+  cache.cacheIssues = (issues) => {
+    issues.forEach(cache.cacheIssue);
+  };
+
+
   cache.uncacheIssues = (issues) => {
     issues.forEach(cache.uncacheIssue);
   };
 
+
   cache.uncacheIssuesOfType = (type) => {
     const issuesOfType = Object.values(cache.issuesByIssueID)
       .filter(issue => issue.type === type);
     cache.uncacheIssues(issuesOfType);
   };
 
+
   // Remove a single entity and all its related issues from the caches
   cache.uncacheEntityID = (entityID) => {
-    const issueIDs = cache.issuesByEntityID[entityID];
-    if (issueIDs) {
-      issueIDs.forEach(issueID => {
+    const entityIssueIDs = cache.issuesByEntityID[entityID];
+    if (entityIssueIDs) {
+      entityIssueIDs.forEach(issueID => {
         const issue = cache.issuesByIssueID[issueID];
         if (issue) {
           cache.uncacheIssue(issue);
-        } else {
+        } else {  // shouldnt happen, clean up
           delete cache.issuesByIssueID[issueID];
         }
       });
@@ -849,5 +853,32 @@ function validationCache(which) {
   };
 
 
+  // Return the expandeded set of entityIDs related to issues for the given entityIDs
+  //
+  // Arguments
+  //   `entityIDs` - Array or Set containing entityIDs.
+  //
+  cache.withAllRelatedEntities = (entityIDs) => {
+    let result = new Set();
+    (entityIDs || []).forEach(entityID => {
+      result.add(entityID);  // include self
+
+      const entityIssueIDs = cache.issuesByEntityID[entityID];
+      if (entityIssueIDs) {
+        entityIssueIDs.forEach(issueID => {
+          const issue = cache.issuesByIssueID[issueID];
+          if (issue) {
+            (issue.entityIds || []).forEach(relatedID => result.add(relatedID))
+          } else {  // shouldnt happen, clean up
+            delete cache.issuesByIssueID[issueID];
+          }
+        });
+      }
+    });
+
+    return result;
+  }
+
+
   return cache;
 }