diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index e50fd3b82b..994fb3ac17 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -1901,80 +1901,92 @@ std::vector<GCodeGenerator::InstanceToPrint> GCodeGenerator::sort_print_object_i
 namespace ProcessLayer
 {
 
+static std::string emit_custom_color_change_gcode_per_print_z(
+    GCodeGenerator          &gcodegen,
+    const CustomGCode::Item &custom_gcode,
+    unsigned int             current_extruder_id,
+    unsigned int             first_extruder_id, // ID of the first extruder printing this layer.
+    const PrintConfig       &config
+) {
+    const bool single_extruder_multi_material = config.single_extruder_multi_material;
+    const bool single_extruder_printer        = config.nozzle_diameter.size() == 1;
+    const bool color_change                   = custom_gcode.type == CustomGCode::ColorChange;
+
+    std::string gcode;
+
+    int color_change_extruder = -1;
+    if (color_change && custom_gcode.extruder > 0)
+        color_change_extruder = custom_gcode.extruder - 1;
+
+    assert(color_change_extruder >= 0);
+    // Color Change or Tool Change as Color Change.
+    // add tag for processor
+    gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Color_Change) + ",T" + std::to_string(color_change_extruder) + "," + custom_gcode.color + "\n";
+
+    DynamicConfig cfg;
+    cfg.set_key_value("color_change_extruder", new ConfigOptionInt(color_change_extruder));
+    if (single_extruder_multi_material && !single_extruder_printer && color_change_extruder >= 0 && first_extruder_id != unsigned(color_change_extruder)) {
+        //! FIXME_in_fw show message during print pause
+        // FIXME: Why is pause_print_gcode here? Why is it supplied "color_change_extruder"?
+        gcode += gcodegen.placeholder_parser_process("pause_print_gcode", config.pause_print_gcode, current_extruder_id, &cfg);
+        gcode += "\n";
+        gcode += "M117 Change filament for Extruder " + std::to_string(color_change_extruder) + "\n";
+    } else {
+        gcode += gcodegen.placeholder_parser_process("color_change_gcode", config.color_change_gcode, current_extruder_id, &cfg);
+        gcode += "\n";
+        //FIXME Tell G-code writer that M600 filled the extruder, thus the G-code writer shall reset the extruder to unretracted state after
+        // return from M600. Thus the G-code generated by the following line is ignored.
+        // see GH issue #6362
+        gcodegen.writer().unretract();
+    }
+
+    return gcode;
+}
+
     static std::string emit_custom_gcode_per_print_z(
         GCodeGenerator                                          &gcodegen,
-        const CustomGCode::Item 								*custom_gcode,
+        const CustomGCode::Item 								&custom_gcode,
         unsigned int                                             current_extruder_id,
         // ID of the first extruder printing this layer.
         unsigned int                                             first_extruder_id,
         const PrintConfig                                       &config)
     {
         std::string gcode;
-        bool single_extruder_printer = config.nozzle_diameter.size() == 1;
 
-        if (custom_gcode != nullptr) {
-            // Extruder switches are processed by LayerTools, they should be filtered out.
-            assert(custom_gcode->type != CustomGCode::ToolChange);
+        // Extruder switches are processed by LayerTools, they should be filtered out.
+        assert(custom_gcode.type != CustomGCode::ToolChange);
 
-            CustomGCode::Type gcode_type   = custom_gcode->type;
-            const bool        color_change = gcode_type == CustomGCode::ColorChange;
-            const bool        tool_change  = gcode_type == CustomGCode::ToolChange;
-            // Tool Change is applied as Color Change for a single extruder printer only.
-            assert(!tool_change || single_extruder_printer);
+        CustomGCode::Type gcode_type   = custom_gcode.type;
+        const bool        color_change = gcode_type == CustomGCode::ColorChange;
+        const bool        tool_change  = gcode_type == CustomGCode::ToolChange;
+        // Tool Change is applied as Color Change for a single extruder printer only.
+        assert(!tool_change || config.nozzle_diameter.size() == 1);
 
-            // we should add or not colorprint_change in respect to nozzle_diameter count instead of really used extruders count
-            if (color_change || tool_change) {
-                const bool single_extruder_multi_material = config.single_extruder_multi_material;
-                const bool single_extruder_printer        = config.nozzle_diameter.size() == 1;
+        // we should add or not colorprint_change in respect to nozzle_diameter count instead of really used extruders count
+        if (color_change || tool_change) {
+            gcode += emit_custom_color_change_gcode_per_print_z(gcodegen, custom_gcode, current_extruder_id, first_extruder_id, config);
+        } else {
+            if (gcode_type == CustomGCode::PausePrint) { // Pause print
+                const std::string pause_print_msg = custom_gcode.extra;
 
-                int color_change_extruder = -1;
-                if (color_change && custom_gcode->extruder > 0)
-                    color_change_extruder = custom_gcode->extruder - 1;
-
-                assert(color_change_extruder >= 0);
-		        // Color Change or Tool Change as Color Change.
                 // add tag for processor
-                gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Color_Change) + ",T" + std::to_string(color_change_extruder) + "," + custom_gcode->color + "\n";
+                gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Pause_Print) + "\n";
+                //! FIXME_in_fw show message during print pause
+                if (!pause_print_msg.empty())
+                    gcode += "M117 " + pause_print_msg + "\n";
 
                 DynamicConfig cfg;
-                cfg.set_key_value("color_change_extruder", new ConfigOptionInt(color_change_extruder));
-                if (single_extruder_multi_material && !single_extruder_printer && color_change_extruder >= 0 && first_extruder_id != unsigned(color_change_extruder)) {
-                    //! FIXME_in_fw show message during print pause
-                    // FIXME: Why is pause_print_gcode here? Why is it supplied "color_change_extruder"?
-                    gcode += gcodegen.placeholder_parser_process("pause_print_gcode", config.pause_print_gcode, current_extruder_id, &cfg);
-                    gcode += "\n";
-                    gcode += "M117 Change filament for Extruder " + std::to_string(color_change_extruder) + "\n";
-                } else {
-                    gcode += gcodegen.placeholder_parser_process("color_change_gcode", config.color_change_gcode, current_extruder_id, &cfg);
-                    gcode += "\n";
-                    //FIXME Tell G-code writer that M600 filled the extruder, thus the G-code writer shall reset the extruder to unretracted state after
-                    // return from M600. Thus the G-code generated by the following line is ignored.
-                    // see GH issue #6362
-                    gcodegen.writer().unretract();
-                }
+                cfg.set_key_value("color_change_extruder", new ConfigOptionInt(int(current_extruder_id)));
+                gcode += gcodegen.placeholder_parser_process("pause_print_gcode", config.pause_print_gcode, current_extruder_id, &cfg);
             } else {
-                if (gcode_type == CustomGCode::PausePrint) { // Pause print
-                    const std::string pause_print_msg = custom_gcode->extra;
-
-                    // add tag for processor
-                    gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Pause_Print) + "\n";
-                    //! FIXME_in_fw show message during print pause
-                    if (!pause_print_msg.empty())
-                        gcode += "M117 " + pause_print_msg + "\n";
-
-                    DynamicConfig cfg;
-                    cfg.set_key_value("color_change_extruder", new ConfigOptionInt(int(current_extruder_id)));
-                    gcode += gcodegen.placeholder_parser_process("pause_print_gcode", config.pause_print_gcode, current_extruder_id, &cfg);
-                } else {
-                    // add tag for processor
-                    gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Custom_Code) + "\n";
-                    if (gcode_type == CustomGCode::Template)    // Template Custom Gcode
-                        gcode += gcodegen.placeholder_parser_process("template_custom_gcode", config.template_custom_gcode, current_extruder_id);
-                    else                                        // custom Gcode
-                        gcode += custom_gcode->extra;
-                }
-                gcode += "\n";
+                // add tag for processor
+                gcode += ";" + GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Custom_Code) + "\n";
+                if (gcode_type == CustomGCode::Template)    // Template Custom Gcode
+                    gcode += gcodegen.placeholder_parser_process("template_custom_gcode", config.template_custom_gcode, current_extruder_id);
+                else                                        // custom Gcode
+                    gcode += custom_gcode.extra;
             }
+            gcode += "\n";
         }
 
         return gcode;
@@ -2243,10 +2255,10 @@ LayerResult GCodeGenerator::process_layer(
     // Map from extruder ID to <begin, end> index of skirt loops to be extruded with that extruder.
     std::map<unsigned int, std::pair<size_t, size_t>> skirt_loops_per_extruder;
 
-    if (single_object_instance_idx == size_t(-1)) {
+    if (single_object_instance_idx == size_t(-1) && layer_tools.custom_gcode != nullptr) {
         // Normal (non-sequential) print.
-        std::string custom_gcode = ProcessLayer::emit_custom_gcode_per_print_z(*this, layer_tools.custom_gcode, m_writer.extruder()->id(), first_extruder_id, print.config());
-        if (layer_tools.custom_gcode != nullptr && layer_tools.custom_gcode->type == CustomGCode::ColorChange) {
+        std::string custom_gcode = ProcessLayer::emit_custom_gcode_per_print_z(*this, *layer_tools.custom_gcode, m_writer.extruder()->id(), first_extruder_id, print.config());
+        if (layer_tools.custom_gcode->type == CustomGCode::ColorChange) {
             // We have a color change to do on this layer, but we want to do it immediately before the first extrusion instead of now, in order to fix GH #2672
             m_pending_pre_extrusion_gcode = custom_gcode;
         } else {