diff --git a/examples/scripts/blender/sdf_exporter.py b/examples/scripts/blender/sdf_exporter.py
index 6450d0a46d..b619918c5c 100644
--- a/examples/scripts/blender/sdf_exporter.py
+++ b/examples/scripts/blender/sdf_exporter.py
@@ -50,7 +50,7 @@ def export_sdf(prefix_path):
 
     # 1 model and 1 link
     model = ET.SubElement(sdf, "model", attrib={"name": "test"})
-    static = ET.SubElement(sdf, "static")
+    static = ET.SubElement(model, "static")
     static.text = "true"
     link = ET.SubElement(model, "link", attrib={"name": "testlink"})
     # for each geometry in geometry library add a <visual> tag
@@ -165,8 +165,8 @@ def add_attenuation_tags(light_tag, blender_light):
     uri.text = path.join(meshes_folder_prefix, dae_filename)
 
     surface = ET.SubElement(collision, "surface")
-    contact = ET.SubElement(collision, "contact")
-    collide_bitmask = ET.SubElement(collision, "collide_bitmask")
+    contact = ET.SubElement(surface, "contact")
+    collide_bitmask = ET.SubElement(contact, "collide_bitmask")
     collide_bitmask.text = "0x01"
 
     ## sdf write to file
diff --git a/examples/worlds/nested_model.sdf b/examples/worlds/nested_model.sdf
index 1ff1f267ba..f717a7a87b 100644
--- a/examples/worlds/nested_model.sdf
+++ b/examples/worlds/nested_model.sdf
@@ -8,7 +8,6 @@
     <plugin
       filename="gz-sim-physics-system"
       name="gz::sim::systems::Physics">
-      <engine><filename>gz-physics-tpe-plugin</filename></engine>
     </plugin>
     <plugin
       filename="gz-sim-user-commands-system"
diff --git a/examples/worlds/particle_emitter.sdf b/examples/worlds/particle_emitter.sdf
index a7018b4ed5..0fd5022792 100644
--- a/examples/worlds/particle_emitter.sdf
+++ b/examples/worlds/particle_emitter.sdf
@@ -30,8 +30,6 @@
     <plugin
       filename="gz-sim-physics-system"
       name="gz::sim::systems::Physics">
-      <!-- Use TPE in order to use nested models -->
-      <engine><filename>gz-physics-tpe-plugin</filename></engine>
     </plugin>
     <plugin
       filename="gz-sim-user-commands-system"
diff --git a/src/gui/plugins/joint_position_controller/JointPositionController.cc b/src/gui/plugins/joint_position_controller/JointPositionController.cc
index e202513024..428edb2291 100644
--- a/src/gui/plugins/joint_position_controller/JointPositionController.cc
+++ b/src/gui/plugins/joint_position_controller/JointPositionController.cc
@@ -45,9 +45,12 @@ namespace gz::sim::gui
     /// \brief Model holding all the joints.
     public: JointsModel jointsModel;
 
-    /// \brief Model entity being controller.
+    /// \brief Model entity being controlled.
     public: Entity modelEntity{kNullEntity};
 
+    /// \brief Previous model entity being controlled.
+    public: Entity prevModelEntity{kNullEntity};
+
     /// \brief Name of the model
     public: QString modelName{"No model selected"};
 
@@ -212,6 +215,12 @@ void JointPositionController::Update(const UpdateInfo &,
   auto jointEntities = _ecm.EntitiesByComponents(components::Joint(),
       components::ParentEntity(this->dataPtr->modelEntity));
 
+  if (this->dataPtr->prevModelEntity != this->dataPtr->modelEntity)
+  {
+    this->dataPtr->prevModelEntity = this->dataPtr->modelEntity;
+    this->dataPtr->jointsModel.Clear();
+  }
+
   // List all joints
   for (const auto &jointEntity : jointEntities)
   {
diff --git a/src/gui/plugins/view_angle/ViewAngle.cc b/src/gui/plugins/view_angle/ViewAngle.cc
index 5d985a851a..8e035dfb90 100644
--- a/src/gui/plugins/view_angle/ViewAngle.cc
+++ b/src/gui/plugins/view_angle/ViewAngle.cc
@@ -338,7 +338,7 @@ bool ViewAngle::OnMoveToModelService(const gz::msgs::GUICamera &_msg,
   Entity entityId = kNullEntity;
   try
   {
-    entityId = std::get<unsigned int>(visualToMove->UserData("gazebo-entity"));
+    entityId = std::get<uint64_t>(visualToMove->UserData("gazebo-entity"));
   }
   catch(std::bad_variant_access &_e)
   {
diff --git a/src/systems/joint_state_publisher/JointStatePublisher.hh b/src/systems/joint_state_publisher/JointStatePublisher.hh
index c83d9a1197..28d2408091 100644
--- a/src/systems/joint_state_publisher/JointStatePublisher.hh
+++ b/src/systems/joint_state_publisher/JointStatePublisher.hh
@@ -33,8 +33,8 @@ namespace sim
 inline namespace GZ_SIM_VERSION_NAMESPACE {
 namespace systems
 {
-  /// \brief The JointStatePub system publishes state information for
-  /// a model. The published message type is gz::msgs::Model, and the
+  /// \brief The JointStatePublisher system publishes joint state information
+  /// for a model. The published message type is gz::msgs::Model, and the
   /// publication topic is determined by the `<topic>` parameter.
   ///
   /// By default the JointStatePublisher will publish all joints for
@@ -45,7 +45,7 @@ namespace systems
   ///
   /// `<topic>`: Name of the topic to publish to. This parameter is optional,
   /// and if not provided, the joint state will be published to
-  /// "/world/<world_name>/model/<model_name>/state".
+  /// "/world/<world_name>/model/<model_name>/joint_state".
   /// `<joint_name>`: Name of a joint to publish. This parameter can be
   /// specified multiple times, and is optional. All joints in a model will
   /// be published if joint names are not specified.
diff --git a/tutorials/files/video_recorder/video_recorder.png b/tutorials/files/video_recorder/video_recorder.png
index f9b06895c9..65204b6358 100644
Binary files a/tutorials/files/video_recorder/video_recorder.png and b/tutorials/files/video_recorder/video_recorder.png differ
diff --git a/tutorials/move_camera_to_model.md b/tutorials/move_camera_to_model.md
index 25f014c404..0ba5287eeb 100644
--- a/tutorials/move_camera_to_model.md
+++ b/tutorials/move_camera_to_model.md
@@ -10,7 +10,7 @@ This tutorial gives an introduction to Gazebo's service `/gui/move_to/model`. Th
 For example, Let's move the camera to the `box` model looking down from 5 meters away.
 
 ```bash
-ign service  -s /gui/move_to/model --reqtype gz.msgs.GUICamera  --reptype gz.msgs.Boolean -r 'name: "box", pose: {position: {z:5}, orientation: {x:0, y:0, z: -1, w:0}}, projection_type: "orbit"' --timeout 5000
+gz service  -s /gui/move_to/model --reqtype gz.msgs.GUICamera  --reptype gz.msgs.Boolean -r 'name: "box", pose: {position: {z:5}, orientation: {x:0, y:0, z: -1, w:0}}, projection_type: "orbit"' --timeout 5000
 ```
 
 @image html files/move_camera_to_model/box_5.gif
@@ -18,7 +18,7 @@ ign service  -s /gui/move_to/model --reqtype gz.msgs.GUICamera  --reptype gz.msg
 The camera can also be placed far away, for example 20 meters:
 
 ```bash
-ign service  -s /gui/move_to/model --reqtype gz.msgs.GUICamera  --reptype gz.msgs.Boolean -r 'name: "box", pose: {position: {z:20}, orientation: {x:0, y:0, z: -1, w:0}}, projection_type: "orbit"' --timeout 5000
+gz service  -s /gui/move_to/model --reqtype gz.msgs.GUICamera  --reptype gz.msgs.Boolean -r 'name: "box", pose: {position: {z:20}, orientation: {x:0, y:0, z: -1, w:0}}, projection_type: "orbit"' --timeout 5000
 ```
 
 @image html files/move_camera_to_model/box_20.gif
diff --git a/tutorials/terminology.md b/tutorials/terminology.md
index 81dc324c78..8b812fbf37 100644
--- a/tutorials/terminology.md
+++ b/tutorials/terminology.md
@@ -73,7 +73,8 @@ to developers touching the source code.
     more than 1 world.
     * It has a single ECM with all the entities and components
       relevant to the levels / world / performer being simulated.
-        * It's still TBD how to support multiple `<worlds>` in parallel.
+        * It's still [an open task](https://github.com/gazebosim/gz-sim/issues/18)
+          to support multiple `<worlds>` in parallel.
     * It has an event manager.
     * It has a network manager, if simulation is distributed.
     * It loads up a set of systems.
diff --git a/tutorials/video_recorder.md b/tutorials/video_recorder.md
index 42ada67f29..efea6422c2 100644
--- a/tutorials/video_recorder.md
+++ b/tutorials/video_recorder.md
@@ -13,8 +13,9 @@ Gazebo that already has this plugin included in the GUI.
 gz sim -v 4 video_record_dbl_pendulum.sdf
 ```
 
-In this plugin, you should see a single button with a video recorder icon.
-Clicking on the button gives you the video format options that are available.
+In this demo world, you should see a video recorder icon positioned on the top.
+left area of the window along with other buttons. Clicking on the video
+recorder button gives you the video format options that are available.
 
 @image html files/video_recorder/video_recorder.png