diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 3de77b911..770d02a7c 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -977,14 +977,13 @@ Print::ApplyStatus Print::apply(const Model &model, const DynamicPrintConfig &co
                     new_objects = true;
                     if (it_old != old.end())
                         const_cast<PrintObjectStatus*>(*it_old)->status = PrintObjectStatus::Deleted;
-                } else if ((*it_old)->print_object->copies() != new_instances.copies) {
+                } else {
                     // The PrintObject already exists and the copies differ.
                     if ((*it_old)->print_object->copies().size() != new_instances.copies.size())
                         update_apply_status(this->invalidate_step(psWipeTower));
 					if ((*it_old)->print_object->set_copies(new_instances.copies)) {
 						// Invalidated
-						static PrintStep steps[] = { psSkirt, psBrim, psGCodeExport };
-						update_apply_status(this->invalidate_multiple_steps(steps, steps + 3));
+						update_apply_status(this->invalidate_steps({ psSkirt, psBrim, psGCodeExport }));
 					}
 					print_objects_new.emplace_back((*it_old)->print_object);
 					const_cast<PrintObjectStatus*>(*it_old)->status = PrintObjectStatus::Reused;
@@ -1002,10 +1001,8 @@ Print::ApplyStatus Print::apply(const Model &model, const DynamicPrintConfig &co
                     delete pos.print_object;
 					deleted_objects = true;
                 }
-			if (deleted_objects) {
-				static PrintStep steps[] = { psSkirt, psBrim, psWipeTower, psGCodeExport };
-				update_apply_status(this->invalidate_multiple_steps(steps, steps + 4));
-			}
+			if (new_objects || deleted_objects)
+				update_apply_status(this->invalidate_steps({ psSkirt, psBrim, psWipeTower, psGCodeExport }));
             update_apply_status(new_objects);
         }
         print_object_status.clear();
diff --git a/src/libslic3r/Print.hpp b/src/libslic3r/Print.hpp
index dfa5cc485..d2dc81755 100644
--- a/src/libslic3r/Print.hpp
+++ b/src/libslic3r/Print.hpp
@@ -268,8 +268,9 @@ public:
     bool invalidate_state_by_config_options(const std::vector<t_config_option_key> &opt_keys);
     bool invalidate_step(PrintObjectStep step);
 	template<typename StepTypeIterator>
-	bool invalidate_multiple_steps(StepTypeIterator step_begin, StepTypeIterator step_end) { return m_state.invalidate_multiple(step_begin, step_end, m_mutex, m_cancel_callback); }
-	bool invalidate_all_steps();
+	bool invalidate_steps(StepTypeIterator step_begin, StepTypeIterator step_end) { return m_state.invalidate_multiple(step_begin, step_end, this->cancel_mutex(), this->cancel_callback()); }
+	bool invalidate_steps(std::initializer_list<PrintObjectStep> il) { return m_state.invalidate_multiple(il.begin(), il.end(), this->cancel_mutex(), this->cancel_callback()); }
+	bool invalidate_all_steps() { return m_state.invalidate_all(this->cancel_mutex(), this->cancel_callback()); }
     bool is_step_done(PrintObjectStep step) const { return m_state.is_done(step); }
 
     // To be used over the layer_height_profile of both the PrintObject and ModelObject
@@ -318,6 +319,9 @@ private:
     void _generate_support_material();
 
     bool is_printable() const { return ! m_copies.empty(); }
+	// Implemented in cpp due to cyclic dependencies between Print and PrintObject.
+	tbb::mutex&            cancel_mutex();
+    std::function<void()>  cancel_callback();
 
     Print                                  *m_print;
     ModelObject                            *m_model_object;
@@ -534,7 +538,8 @@ protected:
 	void                set_done(PrintStep step) { m_state.set_done(step, m_mutex); throw_if_canceled(); }
     bool                invalidate_step(PrintStep step);
 	template<typename StepTypeIterator>
-	bool				invalidate_multiple_steps(StepTypeIterator step_begin, StepTypeIterator step_end) { return m_state.invalidate_multiple(step_begin, step_end, m_mutex, m_cancel_callback); }
+	bool				invalidate_steps(StepTypeIterator step_begin, StepTypeIterator step_end) { return m_state.invalidate_multiple(step_begin, step_end, m_mutex, m_cancel_callback); }
+    bool                invalidate_steps(std::initializer_list<PrintStep> il) { return m_state.invalidate_multiple(il.begin(), il.end(), m_mutex, m_cancel_callback); }
     bool                invalidate_all_steps() { return m_state.invalidate_all(m_mutex, m_cancel_callback); }
 
     // methods for handling regions
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index b7b33087f..6527a7272 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -99,11 +99,9 @@ bool PrintObject::set_copies(const Points &points)
     // Invalidate and set copies.
     bool invalidated = false;
     if (copies != m_copies) {
-        invalidated = m_print->invalidate_step(psSkirt);
-        invalidated |= m_print->invalidate_step(psBrim);
+        invalidated = m_print->invalidate_steps({ psSkirt, psBrim, psGCodeExport });
         if (copies.size() != m_copies.size())
             invalidated |= m_print->invalidate_step(psWipeTower);
-        invalidated |= m_print->invalidate_step(psGCodeExport);
         m_copies = copies;
     }
     return invalidated;
@@ -590,21 +588,16 @@ bool PrintObject::invalidate_step(PrintObjectStep step)
     // propagate to dependent steps
     if (step == posPerimeters) {
         invalidated |= this->invalidate_step(posPrepareInfill);
-        invalidated |= m_print->invalidate_step(psSkirt);
-        invalidated |= m_print->invalidate_step(psBrim);
+        invalidated |= m_print->invalidate_steps({ psSkirt, psBrim });
     } else if (step == posPrepareInfill) {
         invalidated |= this->invalidate_step(posInfill);
     } else if (step == posInfill) {
-        invalidated |= m_print->invalidate_step(psSkirt);
-        invalidated |= m_print->invalidate_step(psBrim);
+        invalidated |= m_print->invalidate_steps({ psSkirt, psBrim });
     } else if (step == posSlice) {
-        invalidated |= this->invalidate_step(posPerimeters);
-        invalidated |= this->invalidate_step(posSupportMaterial);
+        invalidated |= this->invalidate_steps({ posPerimeters, posSupportMaterial });
         invalidated |= m_print->invalidate_step(psWipeTower);
-    } else if (step == posSupportMaterial) {
-        invalidated |= m_print->invalidate_step(psSkirt);
-        invalidated |= m_print->invalidate_step(psBrim);
-    }
+    } else if (step == posSupportMaterial)
+        invalidated |= m_print->invalidate_steps({ psSkirt, psBrim });
 
     // Wipe tower depends on the ordering of extruders, which in turn depends on everything.
     // It also decides about what the wipe_into_infill / wipe_into_object features will do,
@@ -613,11 +606,6 @@ bool PrintObject::invalidate_step(PrintObjectStep step)
     return invalidated;
 }
 
-bool PrintObject::invalidate_all_steps() 
-{ 
-    return m_state.invalidate_all(m_print->m_mutex, m_print->m_cancel_callback);
-}
-
 bool PrintObject::has_support_material() const
 {
     return m_config.support_material
@@ -2254,4 +2242,15 @@ void PrintObject::adjust_layer_height_profile(coordf_t z, coordf_t layer_thickne
     layer_height_profile_valid = false;
 }
 
+tbb::mutex& PrintObject::cancel_mutex()
+{
+	return m_print->m_mutex;
+}
+
+std::function<void()> PrintObject::cancel_callback()
+{
+	return m_print->m_cancel_callback;
+}
+
+
 } // namespace Slic3r