diff --git a/packages/frontend-2/components/viewer/filters/filter/Header.vue b/packages/frontend-2/components/viewer/filters/filter/Header.vue
index 5e2bca8a5..429206e46 100644
--- a/packages/frontend-2/components/viewer/filters/filter/Header.vue
+++ b/packages/frontend-2/components/viewer/filters/filter/Header.vue
@@ -95,10 +95,6 @@ import { useFilterUtilities } from '~/lib/viewer/composables/filtering/filtering
 import { useFilterColoringHelpers } from '~/lib/viewer/composables/filtering/coloringHelpers'
 import type { FilterData } from '~/lib/viewer/helpers/filters/types'
 import { FilterType } from '~/lib/viewer/helpers/filters/types'
-import {
-  useHighlightedObjectsUtilities,
-  useSelectionUtilities
-} from '~/lib/viewer/composables/ui'
 
 const props = defineProps<{
   filter: FilterData
@@ -112,8 +108,6 @@ const { removeActiveFilter, toggleFilterApplied, getPropertyName, filters } =
   useFilterUtilities()
 
 const { toggleColorFilter } = useFilterColoringHelpers()
-const { clearHighlightedObjects } = useHighlightedObjectsUtilities()
-const { clearSelection } = useSelectionUtilities()
 
 const emit = defineEmits<{
   swapProperty: [filterId: string]
@@ -124,8 +118,6 @@ const isColoringActive = computed(() => {
 })
 
 const removeFilter = () => {
-  clearHighlightedObjects()
-  clearSelection()
   removeActiveFilter(props.filter.id)
 }
 
@@ -134,8 +126,6 @@ const toggleVisibility = () => {
 }
 
 const toggleColors = () => {
-  clearHighlightedObjects()
-  clearSelection()
   toggleColorFilter(props.filter.id)
 }
 
diff --git a/packages/frontend-2/components/viewer/models/Card.vue b/packages/frontend-2/components/viewer/models/Card.vue
index a901f7917..186739e63 100644
--- a/packages/frontend-2/components/viewer/models/Card.vue
+++ b/packages/frontend-2/components/viewer/models/Card.vue
@@ -140,7 +140,7 @@ const { hideObjects, showObjects, isolateObjects, unIsolateObjects } =
 const { zoom } = useCameraUtilities()
 const { items } = useInjectedViewerRequestedResources()
 const { resourceItems } = useInjectedViewerLoadedResources()
-const { addToSelectionFromObjectIds, clearSelection } = useSelectionUtilities()
+const { addToSelectionFromObjectIds } = useSelectionUtilities()
 
 const {
   viewer: {
@@ -313,7 +313,6 @@ const handleClick = () => {
   if (!props.isExpanded) {
     emit('toggle-expansion')
   } else {
-    clearSelection()
     addToSelectionFromObjectIds(modelObjectIds.value)
   }
 }
diff --git a/packages/frontend-2/lib/viewer/composables/setup/filters.ts b/packages/frontend-2/lib/viewer/composables/setup/filters.ts
index 66bfdab7a..cb6b8e5f7 100644
--- a/packages/frontend-2/lib/viewer/composables/setup/filters.ts
+++ b/packages/frontend-2/lib/viewer/composables/setup/filters.ts
@@ -1,11 +1,12 @@
 import type { FilterData } from '~/lib/viewer/helpers/filters/types'
 import type { SpeckleObject } from '@speckle/viewer'
 import type { Raw } from 'vue'
-import { FilteringExtension } from '@speckle/viewer'
+import { FilteringExtension, SelectionExtension } from '@speckle/viewer'
 import { watchTriggerable } from '@vueuse/core'
 import { useInjectedViewerState } from '~/lib/viewer/composables/setup'
 import { useOnViewerLoadComplete } from '~/lib/viewer/composables/viewer'
 import { useFilteringDataStore } from '~/lib/viewer/composables/filtering/dataStore'
+import { HighlightExtension } from '~/lib/viewer/composables/setup/highlighting'
 
 /**
  * Setup composable for filter-related state
@@ -61,6 +62,39 @@ export const useManualFilteringPostSetup = () => {
 
   const filteringExtension = () => instance.getExtension(FilteringExtension)
 
+  /**
+   * Preserve selection and highlighting state during filtering operations
+   * This replicates LegacyViewer's preserveSelectionHighlightFilter function
+   */
+  const preserveSelectionHighlightFilter = <T>(filterFn: () => T): T => {
+    const selectionExtension = instance.getExtension(SelectionExtension)
+    const highlightExtension = instance.getExtension(HighlightExtension)
+
+    // 1. SAVE current state from viewer extensions
+    const selectedObjects = selectionExtension
+      .getSelectedObjects()
+      .map((obj) => obj.id as string)
+    const highlightedObjects =
+      highlightExtension?.getSelectedObjects().map((obj) => obj.id as string) || []
+
+    // 2. CLEAR viewer extensions directly
+    if (selectedObjects.length) selectionExtension.clearSelection()
+    if (highlightedObjects.length && highlightExtension) {
+      highlightExtension.clearSelection()
+    }
+
+    // 3. EXECUTE the filtering operation
+    const result = filterFn()
+
+    // 4. RESTORE to viewer extensions directly
+    if (selectedObjects.length) selectionExtension.selectObjects(selectedObjects)
+    if (highlightedObjects.length && highlightExtension) {
+      highlightExtension.selectObjects(highlightedObjects)
+    }
+
+    return result
+  }
+
   /**
    * Watch for changes to manually isolated object IDs
    */
@@ -69,17 +103,19 @@ export const useManualFilteringPostSetup = () => {
     (newIds, oldIds) => {
       if (!newIds || !oldIds) return
 
-      const extension = filteringExtension()
+      preserveSelectionHighlightFilter(() => {
+        const extension = filteringExtension()
 
-      const toIsolate = newIds.filter((id) => !oldIds.includes(id))
-      if (toIsolate.length > 0) {
-        extension.isolateObjects(toIsolate, 'manual-isolation', true, true)
-      }
+        const toIsolate = newIds.filter((id) => !oldIds.includes(id))
+        if (toIsolate.length > 0) {
+          extension.isolateObjects(toIsolate, 'manual-isolation', true, true)
+        }
 
-      const toUnIsolate = oldIds.filter((id) => !newIds.includes(id))
-      if (toUnIsolate.length > 0) {
-        extension.unIsolateObjects(toUnIsolate, 'manual-isolation', true, true)
-      }
+        const toUnIsolate = oldIds.filter((id) => !newIds.includes(id))
+        if (toUnIsolate.length > 0) {
+          extension.unIsolateObjects(toUnIsolate, 'manual-isolation', true, true)
+        }
+      })
     },
     { deep: true }
   )
@@ -92,17 +128,19 @@ export const useManualFilteringPostSetup = () => {
     (newIds, oldIds) => {
       if (!newIds || !oldIds) return
 
-      const extension = filteringExtension()
+      preserveSelectionHighlightFilter(() => {
+        const extension = filteringExtension()
 
-      const toHide = newIds.filter((id) => !oldIds.includes(id))
-      if (toHide.length > 0) {
-        extension.hideObjects(toHide, 'manual-hiding', false, false)
-      }
+        const toHide = newIds.filter((id) => !oldIds.includes(id))
+        if (toHide.length > 0) {
+          extension.hideObjects(toHide, 'manual-hiding', false, false)
+        }
 
-      const toShow = oldIds.filter((id) => !newIds.includes(id))
-      if (toShow.length > 0) {
-        extension.showObjects(toShow, 'manual-hiding', false)
-      }
+        const toShow = oldIds.filter((id) => !newIds.includes(id))
+        if (toShow.length > 0) {
+          extension.showObjects(toShow, 'manual-hiding', false)
+        }
+      })
     },
     { deep: true }
   )
diff --git a/packages/frontend-2/lib/viewer/composables/setup/highlighting.ts b/packages/frontend-2/lib/viewer/composables/setup/highlighting.ts
index 4edb828f1..ad467bc8b 100644
--- a/packages/frontend-2/lib/viewer/composables/setup/highlighting.ts
+++ b/packages/frontend-2/lib/viewer/composables/setup/highlighting.ts
@@ -15,7 +15,7 @@ import { ViewerRenderPageType } from '~/lib/viewer/helpers/state'
  * Highlighting extension that replicates LegacyViewer's HighlightExtension
  * Uses SelectionExtension but disables default events for UI-only highlighting
  */
-class HighlightExtension extends SelectionExtension {
+export class HighlightExtension extends SelectionExtension {
   public constructor(viewer: IViewer, cameraProvider: CameraController) {
     super(viewer, cameraProvider)
 
@@ -51,20 +51,16 @@ export const useHighlightingPostSetup = () => {
 
   if (pageType.value === ViewerRenderPageType.Presentation) return
 
-  const highlightExtension = ref<HighlightExtension | null>(null)
+  // Create the highlighting extension once during setup
+  instance.createExtension(HighlightExtension)
 
   // Get the highlighting extension instance
-  const getHighlightExtension = () => {
-    if (!highlightExtension.value) {
-      highlightExtension.value = instance.createExtension(HighlightExtension)
-    }
-    return highlightExtension.value
-  }
+  const getHighlightExtensionInstance = () => instance.getExtension(HighlightExtension)
 
   useOnViewerLoadComplete(
     ({ isInitial }) => {
       if (!isInitial) return
-      getHighlightExtension()
+      getHighlightExtensionInstance()
     },
     { initialOnly: true }
   )
@@ -73,7 +69,7 @@ export const useHighlightingPostSetup = () => {
   watch(
     highlightedObjectIds,
     (newIds, oldIds) => {
-      const extension = getHighlightExtension()
+      const extension = getHighlightExtensionInstance()
       if (!extension) return
 
       // Clear all current highlights if new list is empty
@@ -83,8 +79,6 @@ export const useHighlightingPostSetup = () => {
       }
 
       if (oldIds && isEqual(newIds, oldIds)) return
-
-      // Clear and re-select to avoid accumulation
       extension.clearSelection()
       if (newIds.length > 0) {
         extension.selectObjects(newIds)
diff --git a/packages/frontend-2/lib/viewer/composables/setup/postSetup.ts b/packages/frontend-2/lib/viewer/composables/setup/postSetup.ts
index 7754c742b..d0d762717 100644
--- a/packages/frontend-2/lib/viewer/composables/setup/postSetup.ts
+++ b/packages/frontend-2/lib/viewer/composables/setup/postSetup.ts
@@ -67,7 +67,10 @@ import {
 } from '~/lib/viewer/composables/setup/filters'
 import { useFilterUtilities } from '~/lib/viewer/composables/filtering/filtering'
 import { useFilteringSetup } from '~/lib/viewer/composables/filtering/setup'
-import { useHighlightingPostSetup } from '~/lib/viewer/composables/setup/highlighting'
+import {
+  useHighlightingPostSetup,
+  HighlightExtension
+} from '~/lib/viewer/composables/setup/highlighting'
 
 function useViewerLoadCompleteEventHandler() {
   const state = useInjectedViewerState()
@@ -566,12 +569,25 @@ function useViewerFiltersIntegration() {
       ).filter(isNonNullable)
       if (arraysEqual(newIds, oldIds)) return
 
-      state.ui.highlightedObjectIds.value = []
-
       const selectionExtension = instance.getExtension(SelectionExtension)
+      const currentViewerSelection = selectionExtension
+        .getSelectedObjects()
+        .map((obj) => obj.id as string)
+
+      if (
+        currentViewerSelection.length === newIds.length &&
+        difference(currentViewerSelection, newIds).length === 0
+      ) {
+        return
+      }
+
+      state.ui.highlightedObjectIds.value = []
+      const highlightExtension = instance.getExtension(HighlightExtension)
+      if (highlightExtension) {
+        highlightExtension.clearSelection()
+      }
 
       selectionExtension.clearSelection()
-
       if (newVal.length > 0) {
         selectionExtension.selectObjects(newIds)
       }