diff --git a/cura/CuraApplication.py b/cura/CuraApplication.py
index 44a1f4d8a0..4e611cf680 100644
--- a/cura/CuraApplication.py
+++ b/cura/CuraApplication.py
@@ -593,9 +593,12 @@ class CuraApplication(QtApplication):
     def updatePlatformActivity(self, node = None):
         count = 0
         scene_bounding_box = None
+        should_pause = False
         for node in DepthFirstIterator(self.getController().getScene().getRoot()):
-            if type(node) is not SceneNode or (not node.getMeshData() and not hasattr(node, "gcode")):
+            if type(node) is not SceneNode or (not node.getMeshData() and not node.callDecoration("shouldBlockSlicing")):
                 continue
+            if node.callDecoration("shouldBlockSlicing"):
+                should_pause = True
 
             count += 1
             if not scene_bounding_box:
@@ -605,6 +608,16 @@ class CuraApplication(QtApplication):
                 if other_bb is not None:
                     scene_bounding_box = scene_bounding_box + node.getBoundingBox()
 
+        if not should_pause:
+            self.getBackend().continueSlicing()
+            self.setHideSettings(False)
+            if self.getPrintInformation():
+                self.getPrintInformation().setPreSliced(False)
+        else:
+            self.getBackend().pauseSlicing()
+            self.setHideSettings(True)
+            self.getPrintInformation().setPreSliced(True)
+
         if not scene_bounding_box:
             scene_bounding_box = AxisAlignedBox.Null
 
@@ -725,7 +738,7 @@ class CuraApplication(QtApplication):
         for node in DepthFirstIterator(self.getController().getScene().getRoot()):
             if type(node) is not SceneNode:
                 continue
-            if (not node.getMeshData() and not hasattr(node, "gcode")) and not node.callDecoration("isGroup"):
+            if (not node.getMeshData() and node.callDecoration("isSliceable")) and not node.callDecoration("isGroup"):
                 continue  # Node that doesnt have a mesh and is not a group.
             if node.getParent() and node.getParent().callDecoration("isGroup"):
                 continue  # Grouped nodes don't need resetting as their parent (the group) is resetted)
diff --git a/plugins/3MFReader/ThreeMFReader.py b/plugins/3MFReader/ThreeMFReader.py
index 397a63c194..97134bf676 100644
--- a/plugins/3MFReader/ThreeMFReader.py
+++ b/plugins/3MFReader/ThreeMFReader.py
@@ -14,6 +14,7 @@ from cura.Settings.SettingOverrideDecorator import SettingOverrideDecorator
 from UM.Application import Application
 from cura.Settings.ExtruderManager import ExtruderManager
 from cura.QualityManager import QualityManager
+from UM.Scene.SliceableObjectDecorator import SliceableObjectDecorator
 
 import os.path
 import zipfile
@@ -234,6 +235,8 @@ class ThreeMFReader(MeshReader):
         except Exception as e:
             Logger.log("e", "An exception occurred in 3mf reader: %s", e)
 
+        sliceable_decorator = SliceableObjectDecorator()
+        result.addDecorator(sliceable_decorator)
         return result
 
     ##  Create a scale vector based on a unit string.
@@ -263,4 +266,4 @@ class ThreeMFReader(MeshReader):
             Logger.log("w", "Unrecognised unit %s used. Assuming mm instead", unit)
             scale = 1
 
-        return Vector(scale, scale, scale)
\ No newline at end of file
+        return Vector(scale, scale, scale)
diff --git a/plugins/CuraEngineBackend/CuraEngineBackend.py b/plugins/CuraEngineBackend/CuraEngineBackend.py
index 31e35aa778..b77b5da5bd 100644
--- a/plugins/CuraEngineBackend/CuraEngineBackend.py
+++ b/plugins/CuraEngineBackend/CuraEngineBackend.py
@@ -188,14 +188,18 @@ class CuraEngineBackend(Backend):
         self._start_slice_job.start()
         self._start_slice_job.finished.connect(self._onStartSliceCompleted)
 
+    _last_state = BackendState.NotStarted
+
     def pauseSlicing(self):
         self.close()
         self.backendStateChange.emit(BackendState.SlicingDisabled)
 
     def continueSlicing(self):
-        self.backendStateChange.emit(BackendState.NotStarted)
+        if self._last_state == BackendState.SlicingDisabled:
+            self.backendStateChange.emit(BackendState.NotStarted)
 
     def _onBackendStateChanged(self, state):
+        self._last_state = state
         if state == BackendState.SlicingDisabled:
             self._pause_slicing = True
         else:
diff --git a/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py b/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py
index 490690bd27..c4e9554b2c 100644
--- a/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py
+++ b/plugins/CuraEngineBackend/ProcessSlicedLayersJob.py
@@ -60,6 +60,7 @@ class ProcessSlicedLayersJob(Job):
         for node in DepthFirstIterator(self._scene.getRoot()):
             if node.callDecoration("getLayerData"):
                 node.getParent().removeChild(node)
+                break
             if self._abort_requested:
                 if self._progress:
                     self._progress.hide()
diff --git a/plugins/GCodeReader/GCodeReader.py b/plugins/GCodeReader/GCodeReader.py
index af3536c6f1..461f4f70b3 100644
--- a/plugins/GCodeReader/GCodeReader.py
+++ b/plugins/GCodeReader/GCodeReader.py
@@ -19,6 +19,7 @@ catalog = i18nCatalog("cura")
 from cura import LayerDataBuilder
 from cura import LayerDataDecorator
 from cura.LayerPolygon import LayerPolygon
+from UM.Scene.SliceableObjectDecorator import SliceableObjectDecorator
 
 import numpy
 import math
@@ -34,8 +35,6 @@ class GCodeReader(MeshReader):
         self._cancelled = False
         self._message = None
 
-        self._scene_node = None
-
     @staticmethod
     def _getValue(line, code):
         n = line.find(code) + len(code)
@@ -69,13 +68,6 @@ class GCodeReader(MeshReader):
         if message == self._message:
             self._cancelled = True
 
-    def _onParentChanged(self, node):
-        if self._scene_node is not None and self._scene_node.getParent() is None:
-            self._scene_node = None
-            Application.getInstance().getBackend().continueSlicing()
-            Application.getInstance().setHideSettings(False)
-            Application.getInstance().getPrintInformation().setPreSliced(False)
-
     @staticmethod
     def _getNullBoundingBox():
         return AxisAlignedBox(minimum=Vector(0, 0, 0), maximum=Vector(10, 10, 10))
@@ -120,12 +112,8 @@ class GCodeReader(MeshReader):
         Logger.log("d", "Preparing to load %s" % file_name)
         self._cancelled = False
 
-        self._scene_node = SceneNode()
-        self._scene_node.getBoundingBox = self._getNullBoundingBox  # Manually set bounding box, because mesh doesn't have mesh data
-        self._scene_node.gcode = True
-        self._scene_node.parentChanged.connect(self._onParentChanged)
-
-        Application.getInstance().getBackend().pauseSlicing()
+        scene_node = SceneNode()
+        scene_node.getBoundingBox = self._getNullBoundingBox  # Manually set bounding box, because mesh doesn't have mesh data
 
         glist = []
         Application.getInstance().getController().getScene().gcode_list = glist
@@ -257,9 +245,12 @@ class GCodeReader(MeshReader):
         layer_mesh = layer_data_builder.build()
         decorator = LayerDataDecorator.LayerDataDecorator()
         decorator.setLayerData(layer_mesh)
+        scene_node.addDecorator(decorator)
 
-        self._scene_node.removeDecorator("LayerDataDecorator")
-        self._scene_node.addDecorator(decorator)
+        sliceable_decorator = SliceableObjectDecorator()
+        sliceable_decorator.setBlockSlicing(True)
+        sliceable_decorator.setSliceable(False)
+        scene_node.addDecorator(sliceable_decorator)
 
         Logger.log("d", "Finished parsing %s" % file_name)
         self._message.hide()
@@ -267,15 +258,12 @@ class GCodeReader(MeshReader):
         if current_layer == 0:
             Logger.log("w", "File %s doesn't contain any valid layers" % file_name)
 
-        Application.getInstance().getPrintInformation().setPreSliced(True)
-        Application.getInstance().setHideSettings(True)
-
         settings = Application.getInstance().getGlobalContainerStack()
         machine_width = settings.getProperty("machine_width", "value")
         machine_depth = settings.getProperty("machine_depth", "value")
 
-        self._scene_node.setPosition(Vector(-machine_width / 2, 0, machine_depth / 2))
+        scene_node.setPosition(Vector(-machine_width / 2, 0, machine_depth / 2))
 
         Logger.log("d", "Loaded %s" % file_name)
 
-        return self._scene_node
+        return scene_node
diff --git a/plugins/LayerView/LayerPass.py b/plugins/LayerView/LayerPass.py
index 9e610b68d2..ca895619a3 100644
--- a/plugins/LayerView/LayerPass.py
+++ b/plugins/LayerView/LayerPass.py
@@ -49,7 +49,7 @@ class LayerPass(RenderPass):
             if isinstance(node, ToolHandle):
                 tool_handle_batch.addItem(node.getWorldTransformation(), mesh = node.getSolidMesh())
 
-            elif isinstance(node, SceneNode) and (node.getMeshData() or hasattr(node, "gcode")) and node.isVisible():
+            elif isinstance(node, SceneNode) and (node.getMeshData() or not node.callDecoration("isSliceable")) and node.isVisible():
                 layer_data = node.callDecoration("getLayerData")
                 if not layer_data:
                     continue
diff --git a/plugins/X3DReader/X3DReader.py b/plugins/X3DReader/X3DReader.py
index ba31c9ea86..16b8a6a5ae 100644
--- a/plugins/X3DReader/X3DReader.py
+++ b/plugins/X3DReader/X3DReader.py
@@ -10,6 +10,7 @@ from UM.Scene.SceneNode import SceneNode
 from UM.Job import Job
 from math import pi, sin, cos, sqrt
 import numpy
+from UM.Scene.SliceableObjectDecorator import SliceableObjectDecorator
 
 try:
     import xml.etree.cElementTree as ET
@@ -96,6 +97,8 @@ class X3DReader(MeshReader):
             Logger.logException("e", "Exception in X3D reader")
             return None
 
+        sliceable_decorator = SliceableObjectDecorator()
+        node.addDecorator(sliceable_decorator)
         return node
     
     # ------------------------- XML tree traversal