diff --git a/assignment-client/CMakeLists.txt b/assignment-client/CMakeLists.txt
index c73e8e1d34..7750c0a105 100644
--- a/assignment-client/CMakeLists.txt
+++ b/assignment-client/CMakeLists.txt
@@ -13,7 +13,7 @@ setup_memory_debugger()
 link_hifi_libraries(
   audio avatars octree gpu graphics fbx entities
   networking animation recording shared script-engine embedded-webserver
-  controllers physics plugins midi image
+  controllers physics plugins midi image workload
 )
 
 add_dependencies(${TARGET_NAME} oven)
diff --git a/libraries/avatars-renderer/CMakeLists.txt b/libraries/avatars-renderer/CMakeLists.txt
index 40e1607b2a..d3d61ea3fa 100644
--- a/libraries/avatars-renderer/CMakeLists.txt
+++ b/libraries/avatars-renderer/CMakeLists.txt
@@ -14,5 +14,6 @@ include_hifi_library_headers(audio)
 include_hifi_library_headers(entities)
 include_hifi_library_headers(octree)
 include_hifi_library_headers(task)
+include_hifi_library_headers(workload)
 
 target_bullet()
diff --git a/libraries/entities-renderer/CMakeLists.txt b/libraries/entities-renderer/CMakeLists.txt
index 0f33a73e40..92f78e357e 100644
--- a/libraries/entities-renderer/CMakeLists.txt
+++ b/libraries/entities-renderer/CMakeLists.txt
@@ -14,6 +14,7 @@ include_hifi_library_headers(entities)
 include_hifi_library_headers(avatars)
 include_hifi_library_headers(controllers)
 include_hifi_library_headers(task)
+include_hifi_library_headers(workload)
 
 target_bullet()
 target_polyvox()
diff --git a/libraries/entities/CMakeLists.txt b/libraries/entities/CMakeLists.txt
index d6d9058e44..3d43330ebc 100644
--- a/libraries/entities/CMakeLists.txt
+++ b/libraries/entities/CMakeLists.txt
@@ -1,4 +1,4 @@
 set(TARGET_NAME entities)
 setup_hifi_library(Network Script)
 include_directories(SYSTEM "${OPENSSL_INCLUDE_DIR}")
-link_hifi_libraries(shared networking octree avatars graphics)
+link_hifi_libraries(shared workload networking octree avatars graphics)
diff --git a/libraries/entities/src/EntityItem.cpp b/libraries/entities/src/EntityItem.cpp
index ed13a46414..503f55e072 100644
--- a/libraries/entities/src/EntityItem.cpp
+++ b/libraries/entities/src/EntityItem.cpp
@@ -2365,12 +2365,14 @@ QList<EntityDynamicPointer> EntityItem::getActionsOfType(EntityDynamicType typeT
 
 void EntityItem::locationChanged(bool tellPhysics) {
     requiresRecalcBoxes();
-    if (tellPhysics) {
-        _flags |= Simulation::DIRTY_TRANSFORM;
-        EntityTreePointer tree = getTree();
-        if (tree) {
+    EntityTreePointer tree = getTree();
+    if (tree) {
+        if (tellPhysics) {
+            _flags |= Simulation::DIRTY_TRANSFORM;
             tree->entityChanged(getThisPointer());
         }
+        glm::vec4 sphere(getWorldPosition(), 0.5f * glm::length(getScaledDimensions()));
+        tree->queueUpdateSpaceProxy(_spaceIndex, sphere);
     }
     SpatiallyNestable::locationChanged(tellPhysics); // tell all the children, also
     somethingChangedNotification();
diff --git a/libraries/entities/src/EntityItem.h b/libraries/entities/src/EntityItem.h
index 5f84bcc311..97ba8b493f 100644
--- a/libraries/entities/src/EntityItem.h
+++ b/libraries/entities/src/EntityItem.h
@@ -477,6 +477,8 @@ public:
     void setCauterized(bool value) { _cauterized = value; }
     bool getCauterized() const { return _cauterized; }
 
+    void setSpaceIndex(int32_t index) { assert(_spaceIndex == -1); _spaceIndex = index; }
+    int32_t getSpaceIndex() const { return _spaceIndex; }
 signals:
     void requestRenderUpdate();
 
@@ -630,6 +632,7 @@ protected:
     quint64 _lastUpdatedAccelerationTimestamp { 0 };
     quint64 _lastUpdatedQueryAACubeTimestamp { 0 };
 
+    int32_t _spaceIndex { -1 }; // index to proxy in workload::Space
     bool _cauterized { false }; // if true, don't draw because it would obscure 1st-person camera
 };
 
diff --git a/libraries/entities/src/EntityTree.cpp b/libraries/entities/src/EntityTree.cpp
index 60bcc85575..5854357661 100644
--- a/libraries/entities/src/EntityTree.cpp
+++ b/libraries/entities/src/EntityTree.cpp
@@ -560,37 +560,49 @@ void EntityTree::setSimulation(EntitySimulationPointer simulation) {
 }
 
 void EntityTree::deleteEntity(const EntityItemID& entityID, bool force, bool ignoreWarnings) {
-    EntityTreeElementPointer containingElement = getContainingElement(entityID);
-    if (!containingElement) {
+    EntityItemPointer entity;
+    {
+        QReadLocker locker(&_entityMapLock);
+        entity = _entityMap.value(entityID);
+    }
+    if (!entity) {
         if (!ignoreWarnings) {
-            qCWarning(entities) << "EntityTree::deleteEntity() on non-existent entityID=" << entityID;
+            qCWarning(entities) << "EntityTree::deleteEntity() on unknown entityID=" << entityID;
         }
         return;
     }
-
-    EntityItemPointer existingEntity = containingElement->getEntityWithEntityItemID(entityID);
-    if (!existingEntity) {
-        if (!ignoreWarnings) {
-            qCWarning(entities) << "EntityTree::deleteEntity() on non-existant entity item with entityID=" << entityID;
-        }
-        return;
-    }
-
-    if (existingEntity->getLocked() && !force) {
+    if (entity->getLocked() && !force) {
         if (!ignoreWarnings) {
             qCDebug(entities) << "ERROR! EntityTree::deleteEntity() trying to delete locked entity. entityID=" << entityID;
         }
         return;
     }
 
+    if (!ignoreWarnings) {
+        if (!entity->getElement()) {
+            qCWarning(entities) << "EntityTree::deleteEntity() found entity with entityID=" << entityID
+                << " in map but it doesn't know its containing element";
+        } else {
+            // check for element mismatch
+            EntityItemPointer otherEntity = entity->getElement()->getEntityWithEntityItemID(entityID);
+            if (!otherEntity) {
+                qCWarning(entities) << "EntityTree::deleteEntity() on entity with entityID=" << entityID
+                    << " but the containing element of record cannot find it";
+            } else if (otherEntity != entity) {
+                qCWarning(entities) << "EntityTree::deleteEntity() on entity with entityID=" << entityID
+                    << " but the containing element of record found a different entity";
+            }
+        }
+    }
+
     unhookChildAvatar(entityID);
     emit deletingEntity(entityID);
-    emit deletingEntityPointer(existingEntity.get());
+    emit deletingEntityPointer(entity.get());
 
     // NOTE: callers must lock the tree before using this method
     DeleteEntityOperator theOperator(getThisPointer(), entityID);
 
-    existingEntity->forEachDescendant([&](SpatiallyNestablePointer descendant) {
+    entity->forEachDescendant([&](SpatiallyNestablePointer descendant) {
         auto descendantID = descendant->getID();
         theOperator.addEntityIDToDeleteList(descendantID);
         emit deletingEntity(descendantID);
@@ -620,34 +632,46 @@ void EntityTree::deleteEntities(QSet<EntityItemID> entityIDs, bool force, bool i
     // NOTE: callers must lock the tree before using this method
     DeleteEntityOperator theOperator(getThisPointer());
     foreach(const EntityItemID& entityID, entityIDs) {
-        EntityTreeElementPointer containingElement = getContainingElement(entityID);
-        if (!containingElement) {
+        EntityItemPointer entity;
+        {
+            QReadLocker locker(&_entityMapLock);
+            entity = _entityMap.value(entityID);
+        }
+        if (!entity) {
             if (!ignoreWarnings) {
-                qCWarning(entities) << "EntityTree::deleteEntities() on non-existent entityID=" << entityID;
+                qCWarning(entities) << "EntityTree::deleteEntities() on unknown entityID=" << entityID;
             }
             continue;
         }
-
-        EntityItemPointer existingEntity = containingElement->getEntityWithEntityItemID(entityID);
-        if (!existingEntity) {
-            if (!ignoreWarnings) {
-                qCWarning(entities) << "EntityTree::deleteEntities() on non-existent entity item with entityID=" << entityID;
-            }
-            continue;
-        }
-
-        if (existingEntity->getLocked() && !force) {
+        if (entity->getLocked() && !force) {
             if (!ignoreWarnings) {
                 qCDebug(entities) << "ERROR! EntityTree::deleteEntities() trying to delete locked entity. entityID=" << entityID;
             }
             continue;
         }
 
+        if (!ignoreWarnings) {
+            if (!entity->getElement()) {
+                qCWarning(entities) << "EntityTree::deleteEntities() found entity with entityID=" << entityID
+                    << " in map but it doesn't know its containing element";
+            } else {
+                // check for element mismatch
+                EntityItemPointer otherEntity = entity->getElement()->getEntityWithEntityItemID(entityID);
+                if (!otherEntity) {
+                    qCWarning(entities) << "EntityTree::deleteEntities() on entity with entityID=" << entityID
+                        << " but the containing element of record cannot find it";
+                } else if (otherEntity != entity) {
+                    qCWarning(entities) << "EntityTree::deleteEntities() on entity with entityID=" << entityID
+                        << " but the containing element of record found a different entity";
+                }
+            }
+        }
+
         // tell our delete operator about this entityID
         unhookChildAvatar(entityID);
         theOperator.addEntityIDToDeleteList(entityID);
         emit deletingEntity(entityID);
-        emit deletingEntityPointer(existingEntity.get());
+        emit deletingEntityPointer(entity.get());
     }
 
     if (theOperator.getEntities().size() > 0) {
@@ -1209,6 +1233,10 @@ bool EntityTree::verifyNonce(const QString& certID, const QString& nonce, Entity
     return verificationSuccess;
 }
 
+void EntityTree::queueUpdateSpaceProxy(int32_t index, const glm::vec4& sphere) {
+    _spaceUpdates.push_back(std::pair<int32_t, glm::vec4>(index, sphere));
+}
+
 void EntityTree::processChallengeOwnershipRequestPacket(ReceivedMessage& message, const SharedNodePointer& sourceNode) {
     int certIDByteArraySize;
     int textByteArraySize;
@@ -1810,6 +1838,12 @@ void EntityTree::update(bool simulate) {
             }
         });
     }
+
+    // process Space queues
+    _space.deleteProxies(_spaceDeletes);
+    _spaceDeletes.clear();
+    _space.updateProxies(_spaceUpdates);
+    _spaceUpdates.clear();
 }
 
 quint64 EntityTree::getAdjustedConsiderSince(quint64 sinceTime) {
@@ -1979,11 +2013,25 @@ void EntityTree::addEntityMapEntry(EntityItemPointer entity) {
         return;
     }
     _entityMap.insert(id, entity);
+
+    // create a proxy for the entity in the workload/Space container
+    glm::vec4 sphere(entity->getWorldPosition(), 0.5f * glm::length(entity->getScaledDimensions()));
+    int32_t spaceIndex = _space.createProxy(sphere);
+    entity->setSpaceIndex(spaceIndex);
 }
 
 void EntityTree::clearEntityMapEntry(const EntityItemID& id) {
+    // this method only called by DeleteEntityOperator
     QWriteLocker locker(&_entityMapLock);
-    _entityMap.remove(id);
+    QHash<EntityItemID, EntityItemPointer>::iterator itr = _entityMap.find(id);
+    if (itr != _entityMap.end()) {
+        // queue delete from _space BEFORE removing from map
+        int32_t spaceIndex = itr.value()->getSpaceIndex();
+        assert(spaceIndex != -1);
+        _spaceDeletes.push_back(spaceIndex);
+
+        _entityMap.erase(itr);
+    }
 }
 
 void EntityTree::debugDumpMap() {
diff --git a/libraries/entities/src/EntityTree.h b/libraries/entities/src/EntityTree.h
index 90fe342f57..c2d0b229b6 100644
--- a/libraries/entities/src/EntityTree.h
+++ b/libraries/entities/src/EntityTree.h
@@ -17,6 +17,7 @@
 
 #include <Octree.h>
 #include <SpatialParentFinder.h>
+#include <workload/Space.h>
 
 class EntityTree;
 using EntityTreePointer = std::shared_ptr<EntityTree>;
@@ -280,6 +281,8 @@ public:
 
     void setMyAvatar(std::shared_ptr<AvatarData> myAvatar) { _myAvatar = myAvatar; }
 
+    void queueUpdateSpaceProxy(int32_t index, const glm::vec4& sphere);
+
 signals:
     void deletingEntity(const EntityItemID& entityID);
     void deletingEntityPointer(EntityItem* entityID);
@@ -387,6 +390,9 @@ private:
     void validatePop(const QString& certID, const EntityItemID& entityItemID, const SharedNodePointer& senderNode, bool isRetryingValidation);
 
     std::shared_ptr<AvatarData> _myAvatar{ nullptr };
+    workload::Space _space;
+    std::vector< std::pair<int32_t, glm::vec4> > _spaceUpdates;
+    std::vector< int32_t > _spaceDeletes;
 };
 
 #endif // hifi_EntityTree_h
diff --git a/libraries/physics/CMakeLists.txt b/libraries/physics/CMakeLists.txt
index ad082c1a6e..c9df2dfc77 100644
--- a/libraries/physics/CMakeLists.txt
+++ b/libraries/physics/CMakeLists.txt
@@ -7,5 +7,6 @@ include_hifi_library_headers(avatars)
 include_hifi_library_headers(audio)
 include_hifi_library_headers(octree)
 include_hifi_library_headers(animation)
+include_hifi_library_headers(workload)
 
 target_bullet()
diff --git a/libraries/script-engine/CMakeLists.txt b/libraries/script-engine/CMakeLists.txt
index 31436bbf8b..6ef8438bf5 100644
--- a/libraries/script-engine/CMakeLists.txt
+++ b/libraries/script-engine/CMakeLists.txt
@@ -20,3 +20,4 @@ endif ()
 link_hifi_libraries(shared networking octree gpu procedural graphics model-networking ktx recording avatars fbx entities controllers animation audio physics image midi)
 # ui includes gl, but link_hifi_libraries does not use transitive includes, so gl must be explicit
 include_hifi_library_headers(gl)
+include_hifi_library_headers(workload)
diff --git a/libraries/ui/src/OffscreenUi.cpp b/libraries/ui/src/OffscreenUi.cpp
index 0e3c15b965..77264a017c 100644
--- a/libraries/ui/src/OffscreenUi.cpp
+++ b/libraries/ui/src/OffscreenUi.cpp
@@ -27,6 +27,7 @@
 #include "VrMenu.h"
 
 #include "ui/Logging.h"
+#include <iostream> // adebug
 
 #include <PointerManager.h>
 
@@ -619,7 +620,13 @@ class KeyboardFocusHack : public QObject {
 public:
     KeyboardFocusHack() {
         Q_ASSERT(_mainWindow);
+        std::cout << "adebug  _mainWindow = " << (void*)(_mainWindow) << std::endl; // adebug
         QTimer::singleShot(200, [=] {
+            _mainWindow = findMainWindow();
+            std::cout << "adebug  again _mainWindow = " << (void*)(_mainWindow) << std::endl; // adebug
+            std::cout << "adebug  _mainWindow->x() = " << _mainWindow->x() << std::endl;
+            std::cout << "  adebug  _mainWindow->y() = " << _mainWindow->y() << std::endl;
+            std::cout << std::endl;     // adebug
             _hackWindow = new QWindow();
             _hackWindow->setFlags(Qt::FramelessWindowHint);
             _hackWindow->setGeometry(_mainWindow->x(), _mainWindow->y(), 10, 10);
@@ -647,10 +654,11 @@ private:
                 break;
             }
         }
+        std::cout << "adebug  findMainWindow()  result = " << (void*)(result) << std::endl;     // adebug
         return result;
     }
 
-    QWindow* const _mainWindow { findMainWindow() };
+    QWindow* _mainWindow { findMainWindow() };
     QWindow* _hackWindow { nullptr };
 };
 
diff --git a/libraries/workload/src/workload/Space.cpp b/libraries/workload/src/workload/Space.cpp
index 1e2bfb228a..2c38ec9f8b 100644
--- a/libraries/workload/src/workload/Space.cpp
+++ b/libraries/workload/src/workload/Space.cpp
@@ -34,38 +34,26 @@ int32_t Space::createProxy(const Space::Sphere& newSphere) {
     }
 }
 
-void Space::deleteProxy(int32_t proxyId) {
-    if (proxyId >= (int32_t)_proxies.size() || _proxies.empty()) {
-        return;
-    }
-    if (proxyId == (int32_t)_proxies.size() - 1) {
-        // remove proxy on back
-        _proxies.pop_back();
-        if (!_freeIndices.empty()) {
-            // remove any freeIndices on back
-            std::sort(_freeIndices.begin(), _freeIndices.end());
-            while(!_freeIndices.empty() && _freeIndices.back() == (int32_t)_proxies.size() - 1) {
-                _freeIndices.pop_back();
-                _proxies.pop_back();
-            }
-        }
-    } else {
-        _proxies[proxyId].region = Space::REGION_INVALID;
-        _freeIndices.push_back(proxyId);
+void Space::deleteProxies(const std::vector<int32_t>& deadIndices) {
+    for (uint32_t i = 0; i < deadIndices.size(); ++i) {
+        deleteProxy(deadIndices[i]);
     }
 }
 
-void Space::updateProxy(int32_t proxyId, const Space::Sphere& newSphere) {
-    if (proxyId >= (int32_t)_proxies.size()) {
-        return;
+void Space::updateProxies(const std::vector<std::pair<int32_t, Sphere> >& changedProxies) {
+    for (uint32_t i = 0; i < changedProxies.size(); ++i) {
+        int32_t proxyId = changedProxies[i].first;
+        if (proxyId > -1 && proxyId < (int32_t)_proxies.size()) {
+            updateProxy(changedProxies[i].first, changedProxies[i].second);
+        }
     }
-    _proxies[proxyId].sphere = newSphere;
 }
 
 void Space::setViews(const std::vector<Space::View>& views) {
     _views = views;
 }
 
+// TODO?: move this to an algorithm/job?
 void Space::categorizeAndGetChanges(std::vector<Space::Change>& changes) {
     uint32_t numProxies = (uint32_t)_proxies.size();
     uint32_t numViews = (uint32_t)_views.size();
@@ -92,3 +80,31 @@ void Space::categorizeAndGetChanges(std::vector<Space::Change>& changes) {
     }
 }
 
+// private
+void Space::deleteProxy(int32_t proxyId) {
+    if (proxyId > -1 && proxyId < (int32_t)_proxies.size()) {
+        if (proxyId == (int32_t)_proxies.size() - 1) {
+            // remove proxy on back
+            _proxies.pop_back();
+            if (!_freeIndices.empty()) {
+                // remove any freeIndices on back
+                std::sort(_freeIndices.begin(), _freeIndices.end());
+                while(!_freeIndices.empty() && _freeIndices.back() == (int32_t)_proxies.size() - 1) {
+                    _freeIndices.pop_back();
+                    _proxies.pop_back();
+                }
+            }
+        } else {
+            _proxies[proxyId].region = Space::REGION_INVALID;
+            _freeIndices.push_back(proxyId);
+        }
+    }
+}
+
+// private
+void Space::updateProxy(int32_t proxyId, const Space::Sphere& newSphere) {
+    if (proxyId > -1 && proxyId < (int32_t)_proxies.size()) {
+        _proxies[proxyId].sphere = newSphere;
+    }
+}
+
diff --git a/libraries/workload/src/workload/Space.h b/libraries/workload/src/workload/Space.h
index be47cddc4e..3a8dd3c488 100644
--- a/libraries/workload/src/workload/Space.h
+++ b/libraries/workload/src/workload/Space.h
@@ -60,8 +60,8 @@ public:
     Space() {}
 
     int32_t createProxy(const Sphere& sphere);
-    void deleteProxy(int32_t proxyId);
-    void updateProxy(int32_t proxyId, const Sphere& sphere);
+    void deleteProxies(const std::vector<int32_t>& deadIndices);
+    void updateProxies(const std::vector<std::pair<int32_t, Sphere> >& changedProxies);
     void setViews(const std::vector<View>& views);
 
     uint32_t getNumObjects() const { return (uint32_t)(_proxies.size() - _freeIndices.size()); }
@@ -69,6 +69,9 @@ public:
     void categorizeAndGetChanges(std::vector<Change>& changes);
 
 private:
+    void deleteProxy(int32_t proxyId);
+    void updateProxy(int32_t proxyId, const Sphere& sphere);
+
     std::vector<Proxy> _proxies;
     std::vector<View> _views;
     std::vector<int32_t> _freeIndices;
diff --git a/tests/entities/CMakeLists.txt b/tests/entities/CMakeLists.txt
index 6d0bf9f149..b1bfcfd8a5 100644
--- a/tests/entities/CMakeLists.txt
+++ b/tests/entities/CMakeLists.txt
@@ -7,7 +7,7 @@ setup_memory_debugger()
 set_target_properties(${TARGET_NAME} PROPERTIES FOLDER "Tests/manual-tests/")
 
 # link in the shared libraries
-link_hifi_libraries(entities avatars shared octree gpu graphics fbx networking animation audio gl)
+link_hifi_libraries(entities avatars shared workload octree gpu graphics fbx networking animation audio gl)
 
 if (WIN32)
   add_dependency_external_projects(wasapi)
diff --git a/tests/render-perf/CMakeLists.txt b/tests/render-perf/CMakeLists.txt
index 7e61d9550c..ed13aadfa3 100644
--- a/tests/render-perf/CMakeLists.txt
+++ b/tests/render-perf/CMakeLists.txt
@@ -18,7 +18,7 @@ link_hifi_libraries(
     render render-utils 
     graphics fbx model-networking 
     entities entities-renderer audio avatars script-engine 
-    physics procedural midi qml ui
+    physics procedural midi qml ui workload
     ${PLATFORM_GL_BACKEND}
 )