diff --git a/lib/bindings/definitions/IRevitMapperBinding.ts b/lib/bindings/definitions/IRevitMapperBinding.ts
index fc61fec..db2a948 100644
--- a/lib/bindings/definitions/IRevitMapperBinding.ts
+++ b/lib/bindings/definitions/IRevitMapperBinding.ts
@@ -14,6 +14,7 @@ export interface IRevitMapperBinding extends IBinding<IMapperBindingEvents> {
   clearObjectsCategoryAssignment: (objectIds: string[]) => Promise<void>
   clearAllObjectsCategoryAssignments: () => Promise<void>
   getCurrentObjectsMappings: () => Promise<CategoryMapping[]>
+  getCategoryMappingsForObjects: (objectIds: string[]) => Promise<string[]>
 
   // Layer methods
   assignLayerToCategory: (layerIds: string[], categoryValue: string) => Promise<void>
@@ -24,6 +25,7 @@ export interface IRevitMapperBinding extends IBinding<IMapperBindingEvents> {
     layerIds: string[],
     categoryValue: string
   ) => Promise<string[]>
+  getCategoryMappingsForLayers: (layerIds: string[]) => Promise<string[]>
 }
 
 export interface IMapperBindingEvents extends IBindingSharedEvents {
@@ -125,6 +127,21 @@ export class MockedMapperBinding implements IRevitMapperBinding {
     return Promise.resolve(['obj1', 'obj2', 'obj3'])
   }
 
+  public getCategoryMappingsForObjects(objectIds: string[]): Promise<string[]> {
+    console.log('Mock: Getting category mappings for objects', { objectIds })
+    // Mock returning some categories for testing
+    return Promise.resolve(
+      objectIds.length > 1 ? ['OST_Walls', 'OST_Doors'] : ['OST_Walls']
+    )
+  }
+
+  public getCategoryMappingsForLayers(layerIds: string[]): Promise<string[]> {
+    console.log('Mock: Getting category mappings for layers', { layerIds })
+    return Promise.resolve(
+      layerIds.length > 1 ? ['OST_Floors', 'OST_Ceilings'] : ['OST_Floors']
+    )
+  }
+
   public showDevTools(): Promise<void> {
     console.log('Braaaaa, no way!')
     return Promise.resolve()
diff --git a/lib/mapper/revit-categories.ts b/lib/mapper/revit-categories.ts
index ce1f652..7faf6bf 100644
--- a/lib/mapper/revit-categories.ts
+++ b/lib/mapper/revit-categories.ts
@@ -5,97 +5,136 @@ import type { CategoryOption } from './types'
  */
 export const REVIT_CATEGORIES: readonly CategoryOption[] = [
   // INFRASTRUCTURE
-  { value: 'OST_BridgeAbutments', label: 'Bridge Abutments' },
-  { value: 'OST_BridgeFraming', label: 'Bridge Framing' },
-  { value: 'OST_BridgeBearings', label: 'Bridge Bearings' },
+  { value: 'OST_BridgeAbutments', label: 'Abutments' },
+  { value: 'OST_AbutmentFoundations', label: 'Abutment Foundations' },
+  { value: 'OST_AbutmentPiles', label: 'Abutment Piles' },
+  { value: 'OST_AbutmentWalls', label: 'Abutment Walls' },
+  { value: 'OST_ApproachSlabs', label: 'Approach Slabs' },
+  { value: 'OST_BridgeBearings', label: 'Bearings' },
   { value: 'OST_BridgeCables', label: 'Bridge Cables' },
   { value: 'OST_BridgeDecks', label: 'Bridge Decks' },
+  { value: 'OST_BridgeFraming', label: 'Bridge Framing' },
+  { value: 'OST_BridgeArches', label: 'Bridge Arches' },
+  { value: 'OST_BridgeFramingCrossBracing', label: 'Bridge Framing - Cross Bracing' },
+  { value: 'OST_BridgeFramingDiaphragms', label: 'Bridge Framing - Diaphragms' },
+  { value: 'OST_BridgeGirders', label: 'Bridge Framing - Girders' },
+  { value: 'OST_BridgeFramingTrusses', label: 'Bridge Framing - Trusses' },
   { value: 'OST_ExpansionJoints', label: 'Expansion Joints' },
-  { value: 'OST_BridgePiers', label: 'Bridge Piers' },
+  { value: 'OST_BridgePiers', label: 'Piers' },
+  { value: 'OST_PierCaps', label: 'Pier Caps' },
+  { value: 'OST_PierColumns', label: 'Pier Columns' },
+  { value: 'OST_BridgeFoundations', label: 'Pier Foundations' },
+  { value: 'OST_PierPiles', label: 'Pier Piles' },
+  { value: 'OST_BridgeTowers', label: 'Pier Towers' },
+  { value: 'OST_PierWalls', label: 'Pier Walls' },
+  { value: 'OST_StructuralTendons', label: 'Structural Tendons' },
   { value: 'OST_VibrationManagement', label: 'Vibration Management' },
+  { value: 'OST_VibrationDampers', label: 'Vibration Dampers' },
+  { value: 'OST_VibrationIsolators', label: 'Vibration Isolators' },
+
+  // ARCHITECTURE
+  { value: 'OST_AudioVisualDevices', label: 'Audio Visual Devices' },
+  { value: 'OST_Casework', label: 'Casework' },
+  { value: 'OST_Ceilings', label: 'Ceilings' },
+  { value: 'OST_Columns', label: 'Columns' },
+  { value: 'OST_CurtainWallPanels', label: 'Curtain Panels' },
+  // { value: 'OST_CurtaSystem', label: 'Curtain Systems' }, excluded as part of CNX-2299
+  { value: 'OST_CurtainWallMullions', label: 'Curtain Wall Mullions' },
+  { value: 'OST_Doors', label: 'Doors' },
+  { value: 'OST_Entourage', label: 'Entourage' },
+  { value: 'OST_FireProtection', label: 'Fire Protection' },
+  { value: 'OST_Floors', label: 'Floors' },
+  { value: 'OST_FoodServiceEquipment', label: 'Food Service Equipment' },
+  { value: 'OST_Furniture', label: 'Furniture' },
+  { value: 'OST_FurnitureSystems', label: 'Furniture Systems' },
+  { value: 'OST_GenericModel', label: 'Generic Models' },
+  { value: 'OST_Hardscape', label: 'Hardscape' },
+  { value: 'OST_Lines', label: 'Lines' },
+  { value: 'OST_Mass', label: 'Mass' },
+  { value: 'OST_MechanicalControlDevices', label: 'Mechanical Control Devices' },
+  { value: 'OST_MechanicalEquipment', label: 'Mechanical Equipment' },
+  { value: 'OST_MedicalEquipment', label: 'Medical Equipment' },
+  { value: 'OST_Parking', label: 'Parking' },
+  { value: 'OST_Parts', label: 'Parts' },
+  { value: 'OST_Planting', label: 'Planting' },
+  { value: 'OST_PlumbingEquipment', label: 'Plumbing Equipment' },
+  { value: 'OST_PlumbingFixtures', label: 'Plumbing Fixtures' },
+  { value: 'OST_StairsRailing', label: 'Railings' },
+  { value: 'OST_StairsRailingBaluster', label: 'Railings - Balusters' },
+  { value: 'OST_RailingSupport', label: 'Railings - Supports' },
+  { value: 'OST_RailingTermination', label: 'Railings - Terminations' },
+  { value: 'OST_Ramps', label: 'Ramps' },
+  { value: 'OST_Roads', label: 'Roads' },
+  { value: 'OST_Roofs', label: 'Roofs' },
+  { value: 'OST_Signage', label: 'Signage' },
+  { value: 'OST_Site', label: 'Site' },
+  { value: 'OST_SpecialtyEquipment', label: 'Specialty Equipment' },
+  { value: 'OST_Stairs', label: 'Stairs' },
+  { value: 'OST_TemporaryStructure', label: 'Temporary Structures' },
+  { value: 'OST_Topography', label: 'Topography' },
+  { value: 'OST_Toposolid', label: 'Toposolid' },
+  { value: 'OST_VerticalCirculation', label: 'Vertical Circulation' },
+  { value: 'OST_Walls', label: 'Walls' },
+  { value: 'OST_Windows', label: 'Windows' },
 
   // ELECTRICAL
-  { value: 'OST_AudioVisualDevices', label: 'Audio Visual Devices' },
-  { value: 'OST_CableTray', label: 'Cable Tray' },
   { value: 'OST_CableTrayFitting', label: 'Cable Tray Fittings' },
+  { value: 'OST_CableTray', label: 'Cable Trays' },
   { value: 'OST_CommunicationDevices', label: 'Communication Devices' },
+  { value: 'OST_ConduitFittings', label: 'Conduit Fittings' },
   { value: 'OST_Conduit', label: 'Conduits' },
-  { value: 'OST_ConduitFitting', label: 'Conduit Fittings' },
   { value: 'OST_DataDevices', label: 'Data Devices' },
   { value: 'OST_ElectricalEquipment', label: 'Electrical Equipment' },
   { value: 'OST_ElectricalFixtures', label: 'Electrical Fixtures' },
   { value: 'OST_FireAlarmDevices', label: 'Fire Alarm Devices' },
-  { value: 'OST_LightingDevices', label: 'Lighting Devices' },
+  { value: 'OST_LighintgDevices', label: 'Lighting Devices' },
   { value: 'OST_LightingFixtures', label: 'Lighting Fixtures' },
   { value: 'OST_NurseCallDevices', label: 'Nurse Call Devices' },
   { value: 'OST_SecurityDevices', label: 'Security Devices' },
   { value: 'OST_TelephoneDevices', label: 'Telephone Devices' },
 
-  // ARCHITECTURAL
-  { value: 'OST_Casework', label: 'Casework' },
-  { value: 'OST_Ceilings', label: 'Ceilings' },
-  { value: 'OST_Columns', label: 'Columns' },
-  { value: 'OST_CurtainWallMullions', label: 'Curtain Wall Mullions' },
-  { value: 'OST_CurtainWallPanels', label: 'Curtain Panels' },
-  // OST_Curtain_Systems excluded as part of CNX-2299
-  { value: 'OST_Doors', label: 'Doors' },
-  { value: 'OST_Entourage', label: 'Entourage' },
-  { value: 'OST_Floors', label: 'Floors' },
-  { value: 'OST_FoodServiceEquipment', label: 'Food Service Equipment' },
-  { value: 'OST_Furniture', label: 'Furniture' },
-  { value: 'OST_FurnitureSystems', label: 'Furniture Systems' },
-  { value: 'OST_Hardscape', label: 'Hardscape' },
-  { value: 'OST_Parking', label: 'Parking' },
-  { value: 'OST_Planting', label: 'Planting' },
-  { value: 'OST_Railings', label: 'Railings' },
-  { value: 'OST_Ramps', label: 'Ramps' },
-  { value: 'OST_Roads', label: 'Roads' },
-  { value: 'OST_Roofs', label: 'Roofs' },
-  { value: 'OST_Site', label: 'Site' },
-  { value: 'OST_SpecialityEquipment', label: 'Speciality Equipment' },
-  { value: 'OST_Stairs', label: 'Stairs' },
-  { value: 'OST_Topography', label: 'Topography' },
-  { value: 'OST_Toposolid', label: 'Toposolid' },
-  { value: 'OST_Walls', label: 'Walls' },
-  { value: 'OST_Windows', label: 'Windows' },
-
-  // STRUCTURAL
-  // OST_StructuralColumns excluded as part of CNX-2299
-  { value: 'OST_StructuralConnections', label: 'Structural Connections' },
+  // STRUCTURE
+  { value: 'OST_Coupler', label: 'Structural Rebar Couplers' },
+  { value: 'OST_FabricAreas', label: 'Structural Fabric Areas' },
+  { value: 'OST_StructConnections', label: 'Structural Connections' },
+  { value: 'OST_StructConnectionAnchors', label: 'Structural Connections - Anchors' },
+  { value: 'OST_StructConnectionBolts', label: 'Structural Connections - Bolts' },
+  { value: 'OST_StructConnectionPlates', label: 'Structural Connections - Plates' },
+  { value: 'OST_StructConnectionProfiles', label: 'Structural Connections - Profiles' },
+  {
+    value: 'OST_StructConnectionShearStuds',
+    label: 'Structural Connections - Shear Studs'
+  },
+  { value: 'OST_StructConnectionWelds', label: 'Structural Connections - Welds' },
+  // { value: 'OST_StructuralColumns', label: 'Structural Columns' }, excluded as part of CNX-2299
   { value: 'OST_StructuralFoundation', label: 'Structural Foundations' },
   { value: 'OST_StructuralFraming', label: 'Structural Framing' },
-  { value: 'OST_StructuralFramingSystem', label: 'Structural Beam Systems' },
-  { value: 'OST_StructuralFabricAreas', label: 'Structural Fabric Areas' },
-  { value: 'OST_Rebar', label: 'Rebar' },
-  { value: 'OST_StructuralStiffener', label: 'Structural Stiffeners' },
-  { value: 'OST_StructuralTendons', label: 'Structural Tendons' },
   { value: 'OST_StructuralTruss', label: 'Structural Trusses' },
+  { value: 'OST_Rebar', label: 'Structural Rebar' },
 
   // MECHANICAL
+  { value: 'OST_DuctTerminal', label: 'Air Terminals' },
   { value: 'OST_DuctAccessory', label: 'Duct Accessories' },
-  { value: 'OST_DuctCurves', label: 'Ducts' },
   { value: 'OST_DuctFitting', label: 'Duct Fittings' },
-  { value: 'OST_DuctSystem', label: 'Duct Systems' },
-  { value: 'OST_MechanicalEquipment', label: 'Mechanical Equipment' },
-  { value: 'OST_PlumbingEquipment', label: 'Plumbing Equipment' },
-  { value: 'OST_PlumbingFixtures', label: 'Plumbing Fixtures' },
+  { value: 'OST_PlaceHolderDucts', label: 'Duct Placeholders' },
+  { value: 'OST_DuctCurves', label: 'Ducts' },
+  { value: 'OST_MEPAncillaryFraming', label: 'MEP Ancillary Framing' },
 
   // PIPING
   { value: 'OST_PipeAccessory', label: 'Pipe Accessories' },
-  { value: 'OST_PipeCurves', label: 'Pipes' },
   { value: 'OST_PipeFitting', label: 'Pipe Fittings' },
+  { value: 'OST_PlaceHolderPipes', label: 'Pipe Placeholders' },
+  { value: 'OST_PipeSegments', label: 'Pipe Segments' },
+  { value: 'OST_PipeCurves', label: 'Pipes' },
   { value: 'OST_Sprinklers', label: 'Sprinklers' },
 
   // GENERAL/MULTI-DISCIPLINE
-  { value: 'OST_FireProtection', label: 'Fire Protection' },
-  { value: 'OST_GenericModel', label: 'Generic Models' },
-  { value: 'OST_Lines', label: 'Lines' },
-  { value: 'OST_Mass', label: 'Mass' },
-  { value: 'OST_MedicalEquipment', label: 'Medical Equipment' },
-  { value: 'OST_Parts', label: 'Parts' },
-  { value: 'OST_Signage', label: 'Signage' },
-  { value: 'OST_TemporaryStructure', label: 'Temporary Structures' },
-  { value: 'OST_VerticalCirculation', label: 'Vertical Circulation' }
+  { value: 'OST_CableTrayRun', label: 'Cable Tray Runs' },
+  { value: 'OST_Coordination_Model', label: 'Coordination Model' },
+  { value: 'OST_DuctSystem', label: 'Duct Systems' },
+  { value: 'OST_PipingSystem', label: 'Piping Systems' },
+  { value: 'OST_StructuralFramingSystem', label: 'Structural Beam Systems' },
+  { value: 'OST_StructuralStiffener', label: 'Structural Stiffeners' }
 ] as const
 
 /**
diff --git a/pages/revit-mapper.vue b/pages/revit-mapper.vue
index e8f4e30..6488537 100644
--- a/pages/revit-mapper.vue
+++ b/pages/revit-mapper.vue
@@ -55,9 +55,9 @@
           <div class="flex-1">
             <FormSelectBase
               key="label"
-              v-model="selectedCategory"
+              v-model="revitMapperStore.selectedCategory"
               name="categoryMapping"
-              placeholder="Select a category"
+              :placeholder="dropdownPlaceholder"
               label="Target Category"
               fixed-height
               size="sm"
@@ -68,9 +68,9 @@
               :allow-unset="false"
               mount-menu-on-body
             >
-              <template #something-selected="{ value }">
+              <template #something-selected>
                 <span class="text-primary text-xs">
-                  {{ Array.isArray(value) ? value[0]?.label : value?.label }}
+                  {{ displayLabel }}
                 </span>
               </template>
               <template #option="{ item }">
@@ -83,7 +83,7 @@
           <FormButton
             color="primary"
             size="sm"
-            :disabled="!selectedCategory"
+            :disabled="!revitMapperStore.selectedCategory?.value"
             @click="assignToCategory()"
           >
             Apply
@@ -193,6 +193,7 @@
 import { storeToRefs } from 'pinia'
 import { ArrowLeftIcon } from '@heroicons/vue/20/solid'
 import { useSelectionStore } from '~/store/selection'
+import { useRevitMapper } from '~/store/revitMapper'
 import type {
   Category,
   CategoryMapping,
@@ -201,15 +202,17 @@ import type {
 
 // Import categories
 import { getAvailableCategories, getCategoryLabel } from '~/lib/mapper/revit-categories'
+import { useMixpanel } from '~/lib/core/composables/mixpanel'
 
 // === STORES ===
 const selectionStore = useSelectionStore()
+const revitMapperStore = useRevitMapper()
 const { selectionInfo } = storeToRefs(selectionStore)
+const { trackEvent } = useMixpanel()
 
 // === STATE ===
 const selectedMappingMode = ref<string>('Selection')
 const mappingModeOptions = ['Selection', 'Layer']
-const selectedCategory = ref<Category | undefined>(undefined)
 const categoryOptions = ref<Category[]>([])
 const mappings = ref<CategoryMapping[]>([])
 
@@ -229,6 +232,11 @@ interface LayerOption {
   name: string
 }
 
+// === MAPPING CATEGORY STATE MGMT ===
+const app = useNuxtApp()
+const { $revitMapperBinding, $baseBinding } = app
+// const categoryState = useRevitCategoryState(categoryOptions, $revitMapperBinding)
+
 // === COMPUTED ===
 const hasTargetsSelected = computed(() => {
   if (selectedMappingMode.value === 'Selection') {
@@ -248,9 +256,23 @@ const currentLayerMappings = computed(() => {
   return selectedMappingMode.value === 'Layer' ? layerMappings.value : []
 })
 
+const dropdownPlaceholder = computed(() => {
+  if (revitMapperStore.categoryStatus) {
+    return revitMapperStore.categoryStatus?.isMultiple
+      ? 'Multiple categories'
+      : 'Select a category'
+  }
+  return undefined
+})
+
+const displayLabel = computed(() => {
+  const multiple = revitMapperStore.categoryStatus?.isMultiple
+  return multiple
+    ? 'Multiple categories'
+    : revitMapperStore.selectedCategory?.label || ''
+})
+
 // === METHODS ===
-const app = useNuxtApp()
-const { $revitMapperBinding, $baseBinding } = app
 
 // Search predicate for category dropdown
 const searchFilterPredicate = (item: Category, query: string) => {
@@ -297,6 +319,12 @@ const confirmModeChange = async () => {
       await $revitMapperBinding?.clearAllLayerCategoryAssignments()
     }
 
+    // Track the manual mode switch
+    trackEvent('DUI3 Action', {
+      name: 'Mapper Mode Changed',
+      mode: selectedMappingMode.value
+    })
+
     // Switch mode
     selectedMappingMode.value = pendingMode.value
     await refreshMappings()
@@ -312,19 +340,38 @@ const confirmModeChange = async () => {
 
 // Assign selected objects/layers to the chosen category
 const assignToCategory = async () => {
-  if (!selectedCategory.value || !hasTargetsSelected.value) return
+  if (!revitMapperStore.selectedCategory?.value || !hasTargetsSelected.value) return
 
   try {
-    if (selectedMappingMode.value === 'Selection') {
-      await $revitMapperBinding?.assignObjectsToCategory(
-        selectionInfo.value?.selectedObjectIds || [],
-        selectedCategory.value.value
-      )
-    } else if (selectedMappingMode.value === 'Layer') {
-      await $revitMapperBinding?.assignLayerToCategory(
-        selectedLayers.value.map((layer) => layer.id),
-        selectedCategory.value.value
-      )
+    let assignedCount = 0
+    const { selectedCategory } = storeToRefs(revitMapperStore)
+    const categoryValue = selectedCategory?.value?.value
+
+    if (selectedMappingMode.value === 'Selection' && categoryValue) {
+      const objectIds = selectionInfo.value?.selectedObjectIds || []
+      await $revitMapperBinding?.assignObjectsToCategory(objectIds, categoryValue)
+      assignedCount = objectIds.length
+
+      // Track the assignment
+      trackEvent('DUI3 Action', {
+        name: 'Mapper Assign Category',
+        category: categoryValue,
+        count: assignedCount,
+        mappingType: 'object'
+      })
+    } else if (selectedMappingMode.value === 'Layer' && categoryValue) {
+      const layerIds = selectedLayers.value.map((layer) => layer.id)
+      await $revitMapperBinding?.assignLayerToCategory(layerIds, categoryValue)
+      assignedCount = selectedLayers.value.length
+
+      // Track the assignment
+      trackEvent('DUI3 Action', {
+        name: 'Mapper Assign Category',
+        category: categoryValue,
+        count: assignedCount,
+        mappingType: 'layer'
+      })
+
       selectedLayers.value = []
     }
 
@@ -384,9 +431,10 @@ const selectMappedObjects = async (mapping: CategoryMapping) => {
   }
 }
 
-// Select mapped layers (highlight objects on those layers)
+// Select mapped layers (highlight objects AND restore UI state)
 const selectMappedLayers = async (layerMapping: LayerCategoryMapping) => {
   try {
+    // 1. Highlight objects in Rhino
     const effectiveObjectIds =
       (await $revitMapperBinding?.getEffectiveObjectsForLayerMapping(
         layerMapping.layerIds,
@@ -396,6 +444,24 @@ const selectMappedLayers = async (layerMapping: LayerCategoryMapping) => {
     if (effectiveObjectIds.length > 0) {
       await $baseBinding?.highlightObjects(effectiveObjectIds)
     }
+
+    // 2. Restore UI state - populate layer selection
+    const layersToSelect = layerOptions.value.filter((layer) =>
+      layerMapping.layerIds.includes(layer.id)
+    )
+    selectedLayers.value = layersToSelect
+
+    // 3. Pre-select category in dropdown
+    const categoryToSelect = categoryOptions.value.find(
+      (cat) => cat.value === layerMapping.categoryValue
+    )
+
+    const { selectedCategory, currentCategories } = storeToRefs(revitMapperStore)
+
+    selectedCategory.value = categoryToSelect
+
+    // 4. Update reactive state
+    currentCategories.value = [layerMapping.categoryValue]
   } catch (error) {
     console.error('Failed to highlight effective objects:', error)
   }
@@ -470,9 +536,14 @@ const loadData = async () => {
 // Refresh both object and layer mappings
 const refreshMappings = async () => {
   try {
+    if (!$revitMapperBinding) {
+      console.warn('No revit mapper binding available')
+      return
+    }
+
     const [rawMappings, rawLayerMappings] = await Promise.all([
-      $revitMapperBinding?.getCurrentObjectsMappings() || [],
-      $revitMapperBinding?.getCurrentLayerMappings() || []
+      $revitMapperBinding.getCurrentObjectsMappings(),
+      $revitMapperBinding.getCurrentLayerMappings()
     ])
 
     // Transform to resolve labels
@@ -502,20 +573,51 @@ const loadAvailableLayers = async (): Promise<LayerOption[]> => {
   }
 }
 
-// Refresh just the layer mappings
-const refreshLayerMappings = async () => {
-  try {
-    const rawLayerMappings =
-      (await $revitMapperBinding?.getCurrentLayerMappings()) || []
+// === WATCHER ===
+// Main watcher
+watch(
+  () => ({
+    mode: selectedMappingMode.value,
+    objectIds: selectionInfo.value?.selectedObjectIds || [],
+    layerIds: selectedLayers.value.map((l) => l.id)
+  }),
+  async ({ mode, objectIds, layerIds }) => {
+    if (mode === 'Selection') {
+      await revitMapperStore.updateFromTargets(objectIds, false)
+    } else if (mode === 'Layer') {
+      // In Layer mode, we need to watch both manual layer selection AND object selection
+      // This keeps dropdowns clear when objects are deselected (like Selection mode)
+      // while still supporting manual layer selection
+      if (layerIds.length > 0) {
+        // User has manually selected layers in UI - use layer mode logic
+        await revitMapperStore.updateFromTargets(layerIds, true)
+      } else {
+        // No manual layer selection - use object mode logic (like Selection mode)
+        // This handles the case where selectMappedLayers populated the UI but objects were deselected
+        await revitMapperStore.updateFromTargets(objectIds, false)
+      }
+    }
+  },
+  { immediate: true, deep: true }
+)
 
-    layerMappings.value = rawLayerMappings.map((mapping) => ({
-      ...mapping,
-      categoryLabel: getCategoryLabel(mapping.categoryValue)
-    }))
-  } catch (error) {
-    console.error('Failed to refresh layer mappings:', error)
+// This handles clearing selectedLayers when objects are deselected in Layer mode
+watch(
+  () => selectionInfo.value?.selectedObjectIds?.length || 0,
+  async (newCount, oldCount) => {
+    // Only act in Layer mode when selection count goes to 0 and we have selected layers
+    if (
+      selectedMappingMode.value === 'Layer' &&
+      newCount === 0 &&
+      oldCount > 0 &&
+      selectedLayers.value.length > 0
+    ) {
+      // nextTick to avoid interfering with the main watcher? not nice :(
+      await nextTick()
+      selectedLayers.value = []
+    }
   }
-}
+)
 
 // === LIFECYCLE ===
 onMounted(async () => {
@@ -537,5 +639,26 @@ onMounted(async () => {
     layerOptions.value = newLayers
     selectedLayers.value = []
   })
+
+  // Track mapper opened with the initial mode (after loadData determines it)
+  trackEvent('DUI3 Action', {
+    name: 'Mapper Opened',
+    mode: selectedMappingMode.value
+  })
 })
+
+// Refresh just layer mappings
+const refreshLayerMappings = async () => {
+  try {
+    const rawLayerMappings =
+      (await $revitMapperBinding?.getCurrentLayerMappings()) || []
+
+    layerMappings.value = rawLayerMappings.map((mapping) => ({
+      ...mapping,
+      categoryLabel: getCategoryLabel(mapping.categoryValue)
+    }))
+  } catch (error) {
+    console.error('Failed to refresh layer mappings:', error)
+  }
+}
 </script>
diff --git a/store/revitMapper.ts b/store/revitMapper.ts
new file mode 100644
index 0000000..9552cb1
--- /dev/null
+++ b/store/revitMapper.ts
@@ -0,0 +1,75 @@
+import { defineStore } from 'pinia'
+import type { Category } from '~/lib/bindings/definitions/IRevitMapperBinding'
+import { REVIT_CATEGORIES } from '~/lib/mapper/revit-categories'
+
+export const useRevitMapper = defineStore('revitMapper', () => {
+  const app = useNuxtApp()
+  const { $revitMapperBinding } = app
+  const currentCategories = ref<string[]>([])
+  const selectedCategory = ref<Category | undefined>()
+  const categoryOptions = REVIT_CATEGORIES
+
+  const categoryStatus = computed(() => {
+    if (currentCategories.value.length === 0) {
+      return undefined
+    }
+
+    if (currentCategories.value.length === 1) {
+      const category = categoryOptions.find(
+        (cat) => cat.value === currentCategories.value[0]
+      )
+      return category ? { label: category.label, value: category.value } : undefined
+    }
+
+    return {
+      label: 'Multiple categories',
+      value: 'multiple',
+      isMultiple: true
+    }
+  })
+
+  const updateFromTargets = async (
+    targetIds: string[],
+    isLayerMode: boolean
+  ): Promise<void> => {
+    if (!targetIds.length || !$revitMapperBinding) {
+      clear()
+      return
+    }
+
+    try {
+      // Call connector method based on mode
+      const categories = isLayerMode
+        ? await $revitMapperBinding.getCategoryMappingsForLayers(targetIds)
+        : await $revitMapperBinding.getCategoryMappingsForObjects(targetIds)
+
+      currentCategories.value = categories
+
+      // Update dropdown selection based on categories found
+      if (categories.length === 1) {
+        selectedCategory.value = categoryOptions.find(
+          (cat) => cat.value === categories[0]
+        )
+      } else {
+        // Multiple or no categories - clear dropdown selection
+        selectedCategory.value = undefined
+      }
+    } catch (error) {
+      console.error('Failed to get category mappings:', error)
+      clear()
+    }
+  }
+
+  const clear = () => {
+    currentCategories.value = []
+    selectedCategory.value = undefined
+  }
+
+  return {
+    currentCategories,
+    selectedCategory,
+    categoryStatus,
+    updateFromTargets,
+    clear
+  }
+})