I've had this XML error sitting in my error log for a while, not sure which mod might be causing it. The game is thus far running fine even with the error present, but considering I have significant slowdown during game startup I'm wondering if there might be something broken somewhere or not loaded correctly.

Error in question:

XML error: <placingDraggableDimensions>1</placingDraggableDimensions> doesn't correspond to any field in type ThingDef. Context: <ThingDef ParentName="BuildingBase"><category>Building</category><thingClass>Building</thingClass><soundImpactDefault>BulletImpact_Metal</soundImpactDefault><selectable>true</selectable><drawerType>MapMeshOnly</drawerType><altitudeLayer>Building</altitudeLayer><terrainAffordanceNeeded>Heavy</terrainAffordanceNeeded><repairEffect>Repair</repairEffect><leaveResourcesWhenKilled>false</leaveResourcesWhenKilled><filthLeaving>Filth_RubbleBuilding</filthLeaving><statBases><SellPriceFactor>0.70</SellPriceFactor><MaxHitPoints>300</MaxHitPoints><WorkToBuild>150</WorkToBuild><Flammability>0.0</Flammability><MeditationFocusStrength>0.25</MeditationFocusStrength></statBases><defName>BoneWall</defName><label>bone wall</label><description>An impassable wall, made of bones and skulls. Capable of holding up a roof.</description><graphicData><texPath>Things/Building/Wall/jecrell_Skull_Wall</texPath><graphicClass>Graphic_Single</graphicClass><linkType>CornerFiller</linkType><linkFlags><li>Wall</li><li>Rock</li></linkFlags><damageData><cornerTL>Damage/Corner</cornerTL><cornerTR>Damage/Corner</cornerTR><cornerBL>Damage/Corner</cornerBL><cornerBR>Damage/Corner</cornerBR><edgeTop>Damage/Edge</edgeTop><edgeBot>Damage/Edge</edgeBot><edgeLeft>Damage/Edge</edgeLeft><edgeRight>Damage/Edge</edgeRight></damageData></graphicData><uiIconPath>Things/Building/Wall/jecrell_Skull_Wall_MenuIcon</uiIconPath><costStuffCount>5</costStuffCount><passability>Impassable</passability><blockWind>true</blockWind><castEdgeShadows>true</castEdgeShadows><fillPercent>1</fillPercent><coversFloor>true</coversFloor><placingDraggableDimensions>1</placingDraggableDimensions><tickerType>Never</tickerType><rotatable>false</rotatable><neverMultiSelect>true</neverMultiSelect><holdsRoof>true</holdsRoof><designationCategory>Structure</designationCategory><staticSunShadowHeight>1.0</staticSunShadowHeight><blockLight>true</blockLight><canOverlapZones>false</canOverlapZones><fertility>0</fertility><costList><BoneItem>5</BoneItem></costList><building><isInert>true</isInert><isPlaceOverableWall>true</isPlaceOverableWall><ai_chillDestination>false</ai_chillDestination><blueprintGraphicData><texPath>Things/Building/Linked/Wall_Blueprint_Atlas</texPath></blueprintGraphicData><relatedBuildCommands><li>Door</li><li>Autodoor</li></relatedBuildCommands></building><comps><li Class="CompProperties_MeditationFocus"><statDef>MeditationFocusStrength</statDef><focusTypes><li>Morbid</li></focusTypes></li></comps><damageMultipliers><li><damageDef>Bomb</damageDef><multiplier>2</multiplier></li><li><damageDef>Thump</damageDef><multiplier>2</multiplier></li></damageMultipliers></ThingDef>
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Log.Error_Patch1 (string)
Verse.XmlToObjectUtils:DoFieldSearch (System.Type,System.Xml.XmlNode,System.Xml.XmlNode)
Verse.DirectXmlToObjectNew:ResolveFieldForNode (System.Type,System.Xml.XmlNode,System.Xml.XmlNode)
(wrapper dynamic-method) Verse.DirectXmlToObjectNew/DummyTypeToHoldDynamicMethods:ParseAndReturnDef_Verse_ThingDef (int,int,System.Xml.XmlNode,System.Type)

My game version is latest (1.6), the modlist includes the majority (though not all) of Vanilla Expanded plus a few other additional mods, including Ancient Mining Industry/Hydroponics/Urban Ruins, as well as Dub's Mint Menus. If I need to post the full list let me know.