diff --git a/src/applications/CMakeLists.txt b/src/applications/CMakeLists.txt
index bf6cd6fe15..1e5f722e1b 100644
--- a/src/applications/CMakeLists.txt
+++ b/src/applications/CMakeLists.txt
@@ -85,23 +85,25 @@ IF(NOT OSGEARTH_BUILD_PLATFORM_IPHONE)
         ADD_SUBDIRECTORY(osgearth_heatmap)
         ADD_SUBDIRECTORY(osgearth_collecttriangles)
 
-        IF(SILVERLINING_FOUND)
-            ADD_SUBDIRECTORY(osgearth_silverlining)
-        ENDIF(SILVERLINING_FOUND)
-
-        IF(TRITON_FOUND)
-            ADD_SUBDIRECTORY(osgearth_triton)
-        ENDIF(TRITON_FOUND)
-
     ENDIF(OSGEARTH_BUILD_EXAMPLES)
     
     IF(OSGEARTH_BUILD_TESTS)
+        SET(TARGET_DEFAULT_LABEL_PREFIX "Test")
+        SET(TARGET_DEFAULT_APPLICATION_FOLDER "Tests")
         add_subdirectory(osgearth_bindless)
         ADD_SUBDIRECTORY(osgearth_drawables)
         ADD_SUBDIRECTORY(osgearth_horizon)
         ADD_SUBDIRECTORY(osgearth_overlayviewer)
         ADD_SUBDIRECTORY(osgearth_shadercomp)
         ADD_SUBDIRECTORY(osgearth_windows)
+
+        IF(SILVERLINING_FOUND)
+            ADD_SUBDIRECTORY(osgearth_silverlining)
+        ENDIF(SILVERLINING_FOUND)
+
+        IF(TRITON_FOUND)
+            ADD_SUBDIRECTORY(osgearth_triton)
+        ENDIF(TRITON_FOUND)
     ENDIF(OSGEARTH_BUILD_TESTS)
 
 ELSE()
diff --git a/src/applications/osgearth_bakefeaturetiles/osgearth_bakefeaturetiles.cpp b/src/applications/osgearth_bakefeaturetiles/osgearth_bakefeaturetiles.cpp
index 60bd9647a4..20c3079f14 100644
--- a/src/applications/osgearth_bakefeaturetiles/osgearth_bakefeaturetiles.cpp
+++ b/src/applications/osgearth_bakefeaturetiles/osgearth_bakefeaturetiles.cpp
@@ -402,7 +402,7 @@ class TileListVisitor : public osgEarth::MultithreadedTileVisitor
     {
     }
 
-    virtual void run(const Profile* mapProfile)
+    void run(const Profile* mapProfile) override
     {
         // Start up the task service
         OE_INFO << "Starting " << _numThreads << " threads " << std::endl;
@@ -419,7 +419,7 @@ class TileListVisitor : public osgEarth::MultithreadedTileVisitor
             this->handleTile(key);
         }
 
-        _group.join();
+        _group->join();
     }    
 
     std::vector< TileKey > _keys;
diff --git a/src/applications/osgearth_bindless/osgearth_bindless.cpp b/src/applications/osgearth_bindless/osgearth_bindless.cpp
index e3aa83c9c4..4b422cddd0 100644
--- a/src/applications/osgearth_bindless/osgearth_bindless.cpp
+++ b/src/applications/osgearth_bindless/osgearth_bindless.cpp
@@ -53,6 +53,8 @@ int main_NV(int argc, char** argv)
     osg::ArgumentParser arguments(&argc, argv);
 
     osgViewer::Viewer viewer(arguments);
+    viewer.setRealizeOperation(new GL3RealizeOperation());
+
     MapNodeHelper().configureView(&viewer);
 
     if (arguments.read("--pause"))
diff --git a/src/applications/osgearth_collecttriangles/osgearth_collecttriangles.cpp b/src/applications/osgearth_collecttriangles/osgearth_collecttriangles.cpp
index 1f99b26ac0..b72222b149 100644
--- a/src/applications/osgearth_collecttriangles/osgearth_collecttriangles.cpp
+++ b/src/applications/osgearth_collecttriangles/osgearth_collecttriangles.cpp
@@ -490,7 +490,7 @@ void computeIntersectionsThreaded(osg::Node* node, std::vector< IntersectionQuer
     pool->set_concurrency(num_threads);
 
     // Poor man's parallel for
-    jobs::jobgroup intersections;
+    auto intersections = jobs::jobgroup::create();
 
     //unsigned int workSize = 500;
     // Try to split the jobs evenly among the threads
@@ -508,7 +508,7 @@ void computeIntersectionsThreaded(osg::Node* node, std::vector< IntersectionQuer
         {
             jobs::context context;
             context.pool = pool;
-            context.group = &intersections;
+            context.group = intersections;
 
             jobs::dispatch([node, curStart, curSize, &queries](Cancelable&) {
                 computeIntersections(node, queries, curStart, curSize);
@@ -525,7 +525,7 @@ void computeIntersectionsThreaded(osg::Node* node, std::vector< IntersectionQuer
         }
     }
     //std::cout << "Dispatched " << numJobs << " jobs" << std::endl;
-    intersections.join();
+    intersections->join();
 }
 
 
diff --git a/src/osgEarth/TerrainOptions b/src/osgEarth/TerrainOptions
index de631e656b..72f64dc4bd 100644
--- a/src/osgEarth/TerrainOptions
+++ b/src/osgEarth/TerrainOptions
@@ -66,12 +66,12 @@ namespace osgEarth
         OE_OPTION(float, tilePixelSize, 512.0f);
         OE_OPTION(float, heightFieldSkirtRatio, 0.0f);
         OE_OPTION(Color, color, Color::White);
-        OE_OPTION(bool, progressive, false);
+        OE_OPTION(bool, progressive, true);
         OE_OPTION(bool, useNormalMaps, true);
         OE_OPTION(bool, normalizeEdges, false);
         OE_OPTION(bool, morphTerrain, true);
         OE_OPTION(bool, morphImagery, true);
-        OE_OPTION(unsigned, mergesPerFrame, 20u);
+        OE_OPTION(unsigned, mergesPerFrame, ~0u);
         OE_OPTION(float, priorityScale, 1.0f);
         OE_OPTION(std::string, textureCompression, {});
         OE_OPTION(unsigned, concurrency, 4u);
@@ -114,15 +114,6 @@ namespace osgEarth
         void setMaxLOD(const unsigned& value);
         const unsigned& getMaxLOD() const;
 
-        //! (Legacy property)
-        //! The minimum level of detail to which the terrain should subdivide (no matter what).
-        //! If you leave this unset, the terrain will subdivide until the map layers
-        //! stop providing data (default behavior). If you set a value, the terrain will subdivide
-        //! to the specified LOD no matter what (and may continue farther if higher-resolution
-        //! data is available).
-        void setMinLOD(const unsigned& value);
-        const unsigned& getMinLOD() const;
-
         //! (Legacy property)
         //! The lowest LOD to display. By default, the terrain begins at LOD 0.
         //! Set this to start the terrain tile mesh at a higher LOD.
@@ -140,11 +131,7 @@ namespace osgEarth
         void setEnableBlending(const bool& value);
         const bool& getEnableBlending() const;
 
-        //! @deprecated
-        //! Whether to compress the normal maps before sending to the GPU
-        void setCompressNormalMaps(const bool& value);
-        const bool& getCompressNormalMaps() const;
-
+        //! (Currently not used)
         //! Minimum level of detail at which to generate elevation-based normal maps,
         //! assuming normal maps have been activated. This mitigates the overhead of 
         //! calculating normal maps for very high altitude scenes where they are no
@@ -164,10 +151,6 @@ namespace osgEarth
         void setTessellationRange(const float& value);
         const float& getTessellationRange() const;
 
-        //! Whether to activate debugging mode
-        void setDebug(const bool& value);
-        const bool& getDebug() const;
-
         //! Render bin number for the terrain
         void setRenderBinNumber(const int& value);
         const int& getRenderBinNumber() const;
@@ -248,12 +231,6 @@ namespace osgEarth
         void setMergesPerFrame(const unsigned& value);
         const unsigned& getMergesPerFrame() const;
 
-        //! Scale factor for background loading priority of terrain tiles.
-        //! Default = 1.0. Make it higher to prioritize terrain loading over
-        //! other modules.
-        void setPriorityScale(const float& value);
-        const float& getPriorityScale() const;
-
         //! Texture compression to use by default on terrain image textures
         void setTextureCompressionMethod(const std::string& method);
         const std::string& getTextureCompressionMethod() const;
@@ -282,6 +259,32 @@ namespace osgEarth
         void setCreateTilesGrouped(const bool& value);
         const bool& getCreateTilesGrouped() const;
 
+        //! @deprecated
+        //! Scale factor for background loading priority of terrain tiles.
+        //! Default = 1.0. Make it higher to prioritize terrain loading over
+        //! other modules.
+        void setPriorityScale(const float& value);
+        const float& getPriorityScale() const;
+
+        //! @deprecated
+        //! Whether to activate debugging mode
+        void setDebug(const bool& value);
+        const bool& getDebug() const;
+
+        //! @deprecated
+        //! Whether to compress the normal maps before sending to the GPU
+        void setCompressNormalMaps(const bool& value);
+        const bool& getCompressNormalMaps() const;
+
+        //! @deprecated
+        //! The minimum level of detail to which the terrain should subdivide (no matter what).
+        //! If you leave this unset, the terrain will subdivide until the map layers
+        //! stop providing data (default behavior). If you set a value, the terrain will subdivide
+        //! to the specified LOD no matter what (and may continue farther if higher-resolution
+        //! data is available).
+        void setMinLOD(const unsigned& value);
+        const unsigned& getMinLOD() const;
+
         TerrainOptionsAPI();
         TerrainOptionsAPI(TerrainOptions*);
         TerrainOptionsAPI(const TerrainOptionsAPI&);
diff --git a/src/osgEarth/Threading b/src/osgEarth/Threading
index 08852ddd9d..77af30e5a4 100644
--- a/src/osgEarth/Threading
+++ b/src/osgEarth/Threading
@@ -18,6 +18,7 @@
  */
 #pragma once
 #include <osgEarth/Export>
+#include <unordered_map>
 
 // bring in weejobs in the jobs namespace
 #define WEEJOBS_EXPORT OSGEARTH_EXPORT
diff --git a/src/osgEarth/TileVisitor b/src/osgEarth/TileVisitor
index 78e04890f9..6399ad8d8a 100644
--- a/src/osgEarth/TileVisitor
+++ b/src/osgEarth/TileVisitor
@@ -141,7 +141,7 @@ namespace osgEarth { namespace Util
 
         unsigned int _numThreads;
 
-        jobs::jobgroup _group;
+        std::shared_ptr<jobs::jobgroup> _group;
     };
 
 
diff --git a/src/osgEarth/TileVisitor.cpp b/src/osgEarth/TileVisitor.cpp
index 7e8d6df258..3975de75dd 100644
--- a/src/osgEarth/TileVisitor.cpp
+++ b/src/osgEarth/TileVisitor.cpp
@@ -239,6 +239,8 @@ MultithreadedTileVisitor::MultithreadedTileVisitor() :
     // We must do this to avoid an error message in OpenSceneGraph b/c the findWrapper method doesn't appear to be threadsafe.
     // This really isn't a big deal b/c this only effects data that is already cached.
     osgDB::ObjectWrapper* wrapper = osgDB::Registry::instance()->getObjectWrapperManager()->findWrapper("osg::Image");
+
+    _group = jobs::jobgroup::create();
 }
 
 MultithreadedTileVisitor::MultithreadedTileVisitor(TileHandler* handler) :
@@ -269,7 +271,7 @@ void MultithreadedTileVisitor::run(const Profile* mapProfile)
     // Produce the tiles
     TileVisitor::run( mapProfile );
 
-    _group.join();
+    _group->join();
 }
 
 bool MultithreadedTileVisitor::handleTile(const TileKey& key)
@@ -297,7 +299,7 @@ bool MultithreadedTileVisitor::handleTile(const TileKey& key)
     jobs::context job;
     job.name = "handleTile";
     job.pool = jobs::get_pool(MTTV);
-    job.group = &_group;
+    job.group = _group;
 
     jobs::dispatch(task, job);
 
diff --git a/src/osgEarth/weejobs.h b/src/osgEarth/weejobs.h
index 960f15c324..6fa254dbf3 100644
--- a/src/osgEarth/weejobs.h
+++ b/src/osgEarth/weejobs.h
@@ -6,18 +6,18 @@
  */
 #pragma once
 #include <atomic>
-#include <mutex>
-#include <thread>
+#include <cfloat>
+#include <chrono>
 #include <condition_variable>
+#include <cstdlib>
 #include <functional>
-#include <vector>
-#include <unordered_map>
-#include <chrono>
+#include <list>
+#include <mutex>
+#include <thread>
 #include <type_traits>
-#include <cstdlib>
-#include <cfloat>
+#include <vector>
 
-// OPTIONAL: Define WEEJOBS_EXPORT if you want to use this library from multiple modules (DLLs)
+ // OPTIONAL: Define WEEJOBS_EXPORT if you want to use this library from multiple modules (DLLs)
 #ifndef WEEJOBS_EXPORT
 #define WEEJOBS_EXPORT
 #endif
@@ -386,7 +386,13 @@ namespace WEEJOBS_NAMESPACE
     * You can then call jobgroup::join() to wait for the whole group
     * to finish.
     */
-    using jobgroup = detail::semaphore;
+    struct jobgroup : public detail::semaphore
+    {
+        static std::shared_ptr<jobgroup> create()
+        {
+            return std::make_shared<jobgroup>();
+        }
+    };
 
     /**
     * Context object you can pass to dispatch(...) to control aspects of
@@ -397,7 +403,7 @@ namespace WEEJOBS_NAMESPACE
         std::string name;
         class jobpool* pool = nullptr;
         std::function<float()> priority = {};
-        jobgroup* group = nullptr;
+        std::shared_ptr<jobgroup> group = nullptr;
     };
 
     /**
@@ -532,34 +538,38 @@ namespace WEEJOBS_NAMESPACE
                         // (Benchmark: https://stackoverflow.com/a/20365638/4218920)
                         // Also note: it is indeed possible for the results of 
                         // priority() to change during the search. We don't care.
-                        int index = -1;
+                        //int index = -1;
+                        std::list<job>::iterator ptr = _queue.end();
                         float highest_priority = -FLT_MAX;
-                        for (unsigned i = 0; i < _queue.size(); ++i)
+                        for (auto iter = _queue.begin(); iter != _queue.end(); ++iter)
                         {
-                            float priority = _queue[i].ctx.priority != nullptr ?
-                                _queue[i].ctx.priority() :
+                            float priority = iter->ctx.priority != nullptr ?
+                                iter->ctx.priority() :
                                 0.0f;
 
-                            if (index < 0 || priority > highest_priority)
+                            if (ptr == _queue.end() || priority > highest_priority)
                             {
-                                index = i;
+                                ptr = iter;
                                 highest_priority = priority;
                             }
                         }
-                        if (index < 0)
-                            index = 0;
 
-                        next = std::move(_queue[index]);
+                        if (ptr == _queue.end())
+                            ptr = _queue.begin();
+
+                        next = std::move(*ptr); // _queue[index]);
                         have_next = true;
 
+                        _queue.erase(ptr);
+
                         // move the last element into the empty position:
-                        if (index < _queue.size() - 1)
-                        {
-                            _queue[index] = std::move(_queue.back());
-                        }
+                        //if (index < _queue.size() - 1)
+                        //{
+                        //    _queue[index] = std::move(_queue.back());
+                        //}
 
                         // and remove the last element.
-                        _queue.erase(_queue.end() - 1);
+                        //_queue.erase(_queue.end() - 1);
                     }
                 }
 
@@ -624,7 +634,8 @@ namespace WEEJOBS_NAMESPACE
         };
 
         std::string _name; // pool name
-        std::vector<job> _queue; // queued operations to run asynchronously
+        std::list<job> _queue;
+        //std::vector<job> _queue; // queued operations to run asynchronously
         mutable std::mutex _queueMutex; // protect access to the queue
         mutable std::mutex _quitMutex; // protects access to _done
         std::atomic<unsigned> _targetConcurrency; // target number of concurrent threads in the pool
@@ -689,18 +700,9 @@ namespace WEEJOBS_NAMESPACE
         {
             inline runtime();
 
-            inline void kill()
-            {
-                _alive = false;
-
-                for (auto& pool : _pools)
-                    if (pool)
-                        pool->stop_threads();
+            inline ~runtime();
 
-                for (auto& pool : _pools)
-                    if (pool)
-                        pool->join_threads();
-            }
+            inline void shutdown();
 
             bool _alive = true;
             std::mutex _mutex;
@@ -806,7 +808,7 @@ namespace WEEJOBS_NAMESPACE
             {
                 if (queuedjob.ctx.group != nullptr)
                 {
-                    queuedjob.ctx.group->reset();
+                    queuedjob.ctx.group->release();
                 }
             }
             _queue.clear();
@@ -840,7 +842,7 @@ namespace WEEJOBS_NAMESPACE
     //! stop all threads, wait for them to exit, and shut down the system
     inline void shutdown()
     {
-        instance().kill();
+        instance().shutdown();
     }
 
     //! Whether the weejobs runtime is still alive (has not been shutdown)
@@ -856,10 +858,29 @@ namespace WEEJOBS_NAMESPACE
         instance()._setThreadName = f;
     }
 
-    // internal
     inline detail::runtime::runtime()
     {
-        std::atexit(shutdown);
+        //nop
+    }
+
+    inline detail::runtime::~runtime()
+    {
+        shutdown();
+    }
+
+    inline void detail::runtime::shutdown()
+    {
+        _alive = false;
+
+        //std::cout << "stopping " << _pools.size() << " threads..." << std::endl;
+        for (auto& pool : _pools)
+            if (pool)
+                pool->stop_threads();
+
+        //std::cout << "joining " << _pools.size() << " threads..." << std::endl;
+        for (auto& pool : _pools)
+            if (pool)
+                pool->join_threads();
     }
 
     // Use this macro ONCE in your application in a .cpp file to 
diff --git a/src/osgEarthDrivers/engine_rex/RexTerrainEngineNode.cpp b/src/osgEarthDrivers/engine_rex/RexTerrainEngineNode.cpp
index 055af8e0e9..0fa1c9454e 100644
--- a/src/osgEarthDrivers/engine_rex/RexTerrainEngineNode.cpp
+++ b/src/osgEarthDrivers/engine_rex/RexTerrainEngineNode.cpp
@@ -573,10 +573,8 @@ RexTerrainEngineNode::refresh(bool forceDirty)
         this->ref();
 
         // Load all the root key tiles.
-        jobs::jobgroup loadGroup;
-
         jobs::context context;
-        context.group = &loadGroup;
+        context.group = jobs::jobgroup::create();
         context.pool = jobs::get_pool(ARENA_LOAD_TILE);
 
         for (unsigned i = 0; i < keys.size(); ++i)
@@ -603,7 +601,7 @@ RexTerrainEngineNode::refresh(bool forceDirty)
         }
 
         // wait for all loadSync calls to complete
-        loadGroup.join();
+        context.group->join();
 
         // release the self-ref.
         this->unref_nodelete();
diff --git a/src/osgEarthDrivers/engine_rex/TileNode.cpp b/src/osgEarthDrivers/engine_rex/TileNode.cpp
index 3aac2adcf5..7f47631027 100644
--- a/src/osgEarthDrivers/engine_rex/TileNode.cpp
+++ b/src/osgEarthDrivers/engine_rex/TileNode.cpp
@@ -436,8 +436,8 @@ TileNode::cull(TerrainCuller* culler)
     // whether it is OK to load data (if necessary)
     bool canLoadData =
         _doNotExpire ||
-        _key.getLOD() == _context->options().getFirstLOD() ||
-        _key.getLOD() >= _context->options().getMinLOD();
+        _key.getLOD() >= _context->options().getFirstLOD();
+        //_key.getLOD() >= _context->options().getMinLOD();
 
     // whether to accept the current surface node and not the children.
     bool canAcceptSurface = false;