Getting this error on startup:

XML error: Duplicate XML node name designatorDropdown in this XML block: <ThingDef ParentName="BuildingBase" Name="PowerConduit"><defName>PowerConduit</defName><label>power conduit</label><description>A bundle of electrical cables for moving power around. Can be placed under walls and other buildings.</description><thingClass>Building</thingClass><category>Building</category><graphicData><texPath>Things/Building/Linked/PowerConduit_Atlas</texPath><graphicClass>Graphic_Single</graphicClass><linkType>Transmitter</linkType><linkFlags><li>PowerConduit</li></linkFlags><damageData><rect>(0,0.35,1,0.3)</rect></damageData></graphicData><uiIconPath>Things/Building/Linked/PowerConduit_MenuIcon</uiIconPath><uiIconScale>0.7</uiIconScale><building><ai_chillDestination>false</ai_chillDestination><isInert>true</isInert><isEdifice>false</isEdifice><blueprintGraphicData><texPath>Things/Building/Linked/PowerConduit_Blueprint_Atlas</texPath></blueprintGraphicData></building><drawerType>MapMeshOnly</drawerType><altitudeLayer>Conduits</altitudeLayer><passability>Standable</passability><leaveResourcesWhenKilled>false</leaveResourcesWhenKilled><resourcesFractionWhenDeconstructed>0</resourcesFractionWhenDeconstructed><statBases><MaxHitPoints>80</MaxHitPoints><WorkToBuild>35</WorkToBuild><Flammability>0.7</Flammability><Beauty>-2</Beauty></statBases><placingDraggableDimensions>1</placingDraggableDimensions><costList><Steel>1</Steel></costList><comps><li Class="CompProperties_Power"><compClass>CompPowerTransmitter</compClass><transmitsPower>true</transmitsPower></li></comps><placeWorkers><li>PlaceWorker_Conduit</li></placeWorkers><rotatable>false</rotatable><selectable>true</selectable><neverMultiSelect>true</neverMultiSelect><soundImpactDefault>BulletImpact_Metal</soundImpactDefault><terrainAffordanceNeeded>Light</terrainAffordanceNeeded><designationCategory>Power</designationCategory><constructEffect>ConstructMetal</constructEffect><clearBuildingArea>false</clearBuildingArea><designationHotKey>Misc1</designationHotKey><researchPrerequisites><li>Electricity</li></researchPrerequisites><designatorDropdown>PowerConduits</designatorDropdown><designatorDropdown>PowerCablesGroup</designatorDropdown></ThingDef>
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Verse.Log:Error (string)
Verse.XmlInheritance:CheckForDuplicateNodes (System.Xml.XmlNode,System.Xml.XmlNode)
Verse.XmlInheritance:ResolveXmlNodeFor (Verse.XmlInheritance/XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodesRecursively (Verse.XmlInheritance/XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodesRecursively (Verse.XmlInheritance/XmlInheritanceNode)
Verse.XmlInheritance:ResolveXmlNodes ()
Verse.XmlInheritance:Resolve ()
Verse.LoadedModManager:ParseAndProcessXML (System.Xml.XmlDocument,System.Collections.Generic.Dictionary`2<System.Xml.XmlNode, Verse.LoadableXmlAsset>)
Verse.LoadedModManager:LoadAllActiveMods ()
Verse.PlayDataLoader:DoPlayLoad ()
Verse.PlayDataLoader:LoadAllPlayData (bool)
Verse.Root/<>c:<Start>b__6_1 ()
Verse.LongEventHandler:RunEventFromAnotherThread (System.Action)
Verse.LongEventHandler/<>c:<UpdateCurrentAsynchronousEvent>b__27_0 ()
System.Threading.ThreadHelper:ThreadStart_Context (object)
System.Threading.ExecutionContext:RunInternal (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool)
System.Threading.ExecutionContext:Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool)
System.Threading.ExecutionContext:Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object)
System.Threading.ThreadHelper:ThreadStart ()