diff --git a/cura/CuraApplication.py b/cura/CuraApplication.py
index 7645e88b7e..4285f9ac1d 100755
--- a/cura/CuraApplication.py
+++ b/cura/CuraApplication.py
@@ -43,7 +43,7 @@ from UM.Scene.Selection import Selection
 from UM.Scene.ToolHandle import ToolHandle
 from UM.Settings.ContainerRegistry import ContainerRegistry
 from UM.Settings.InstanceContainer import InstanceContainer
-from UM.Settings.SettingDefinition import SettingDefinition, DefinitionPropertyType
+from UM.Settings.SettingDefinition import SettingDefinition, DefinitionPropertyType, toIntConversion
 from UM.Settings.SettingFunction import SettingFunction
 from UM.Settings.Validator import Validator
 from UM.View.SelectionPass import SelectionPass  # For typing.
@@ -382,11 +382,12 @@ class CuraApplication(QtApplication):
         SettingDefinition.addSupportedProperty("resolve", DefinitionPropertyType.Function, default=None,
                                                depends_on="value")
 
-        SettingDefinition.addSettingType("extruder", None, str, Validator)
-        SettingDefinition.addSettingType("optional_extruder", None, str, None)
+        SettingDefinition.addSettingType("extruder", None, toIntConversion, Validator)
+        SettingDefinition.addSettingType("optional_extruder", None, toIntConversion, None)
         SettingDefinition.addSettingType("[int]", None, str, None)
 
 
+
     def _initializeSettingFunctions(self):
         """Adds custom property types, settings types, and extra operators (functions).
 
diff --git a/resources/definitions/fdmprinter.def.json b/resources/definitions/fdmprinter.def.json
index b1cbb07904..07e9f2e8f6 100644
--- a/resources/definitions/fdmprinter.def.json
+++ b/resources/definitions/fdmprinter.def.json
@@ -4366,6 +4366,7 @@
                             "default_value": "0",
                             "value": "support_extruder_nr",
                             "enabled": "(support_enable or support_meshes_present) and extruders_enabled_count > 1",
+                            "resolve": "max(extruderValues('support_interface_extruder_nr'))",
                             "settable_per_mesh": false,
                             "settable_per_extruder": false,
                             "children":
@@ -4378,6 +4379,7 @@
                                     "default_value": "0",
                                     "value": "support_interface_extruder_nr",
                                     "enabled": "(support_enable or support_meshes_present) and extruders_enabled_count > 1",
+                                    "resolve": "max(extruderValues('support_roof_extruder_nr'))",
                                     "settable_per_mesh": false,
                                     "settable_per_extruder": false
                                 },
@@ -4389,6 +4391,7 @@
                                     "default_value": "0",
                                     "value": "support_interface_extruder_nr",
                                     "enabled": "(support_enable or support_meshes_present) and extruders_enabled_count > 1",
+                                    "resolve": "max(extruderValues('support_bottom_extruder_nr'))",
                                     "settable_per_mesh": false,
                                     "settable_per_extruder": false
                                 }
@@ -5421,6 +5424,7 @@
                     "default_value": "0",
                     "value": "int(defaultExtruderPosition())",
                     "enabled": "extruders_enabled_count > 1 and (resolveOrValue('adhesion_type') != 'none' or resolveOrValue('prime_tower_brim_enable'))",
+                    "resolve": "max(extruderValues('adhesion_extruder_nr'))",
                     "settable_per_mesh": false,
                     "settable_per_extruder": false,
                     "children":
@@ -5444,6 +5448,7 @@
                             "default_value": "0",
                             "value": "adhesion_extruder_nr",
                             "enabled": "extruders_enabled_count > 1 and resolveOrValue('adhesion_type') == 'raft'",
+                            "resolve": "max(extruderValues('raft_base_extruder_nr'))",
                             "settable_per_mesh": false,
                             "settable_per_extruder": false
                         },
@@ -5455,6 +5460,7 @@
                             "default_value": "0",
                             "value": "adhesion_extruder_nr",
                             "enabled": "extruders_enabled_count > 1 and resolveOrValue('adhesion_type') == 'raft'",
+                            "resolve": "max(extruderValues('raft_interface_extruder_nr'))",
                             "settable_per_mesh": false,
                             "settable_per_extruder": false
                         },
@@ -5466,6 +5472,7 @@
                             "default_value": "0",
                             "value": "adhesion_extruder_nr",
                             "enabled": "extruders_enabled_count > 1 and resolveOrValue('adhesion_type') == 'raft'",
+                            "resolve": "max(extruderValues('raft_surface_extruder_nr'))",
                             "settable_per_mesh": false,
                             "settable_per_extruder": false
                         }