diff --git a/src/ui/sidebar/tree/SidebarTree.tsx b/src/ui/sidebar/tree/SidebarTree.tsx
index d736a5b54..25b690c0b 100644
--- a/src/ui/sidebar/tree/SidebarTree.tsx
+++ b/src/ui/sidebar/tree/SidebarTree.tsx
@@ -820,9 +820,13 @@ export function SidebarTree({
     getItemKey: (index) => {
       const row = visibleRows[index];
       if (!row) return index;
+      // Group-by views (e.g. by tags) can list the same host under several
+      // group folders, so parentPath is folded in to keep each occurrence's
+      // key unique -- a shared key across rows made the virtualizer collide
+      // their measured positions and render them stacked on top of each other.
       return isFolder(row.item)
         ? `folder:${row.item.path ?? row.item.name}`
-        : `host:${row.item.id}`;
+        : `${row.parentPath}>host:${row.item.id}`;
     },
   });
 
diff --git a/src/ui/sidebar/tree/visible-rows.ts b/src/ui/sidebar/tree/visible-rows.ts
index 8baad6f10..fe123c926 100644
--- a/src/ui/sidebar/tree/visible-rows.ts
+++ b/src/ui/sidebar/tree/visible-rows.ts
@@ -34,7 +34,18 @@ export function folderHasMatch(folder: HostFolder, query: string): boolean {
   return false;
 }
 
-export type VirtualRow = { item: Host | HostFolder; depth: number };
+/** Sentinel parent for rows sitting at the tree root (no folder). */
+export const ROOT_PARENT = "__root__";
+
+// parentPath identifies which folder/group a row was collected under. Group-by
+// views (e.g. group by tags) can list the same host under several synthetic
+// group folders, so the host id alone isn't a unique row identity -- the
+// virtualizer needs parentPath+id to tell those rows apart.
+export type VirtualRow = {
+  item: Host | HostFolder;
+  depth: number;
+  parentPath: string;
+};
 
 function collectVisibleHostRows(
   host: Host,
@@ -42,9 +53,10 @@ function collectVisibleHostRows(
   closedHostParents: Set<string>,
   out: VirtualRow[],
   depth: number,
+  parentPath: string,
 ): void {
   if (!query || hostMatchesQuery(host, query) || hostHasMatch(host, query)) {
-    out.push({ item: host, depth });
+    out.push({ item: host, depth, parentPath });
   } else {
     return;
   }
@@ -57,7 +69,14 @@ function collectVisibleHostRows(
   const isOpen = query ? true : !closedHostParents.has(hostExpandKey(host));
   if (!isOpen) return;
   for (const child of childHosts) {
-    collectVisibleHostRows(child, query, closedHostParents, out, depth + 1);
+    collectVisibleHostRows(
+      child,
+      query,
+      closedHostParents,
+      out,
+      depth + 1,
+      `${parentPath}>host:${host.id}`,
+    );
   }
 }
 
@@ -68,13 +87,15 @@ export function collectVisibleRows(
   out: VirtualRow[] = [],
   depth = 0,
   closedHostParents: Set<string> = new Set(),
+  parentPath: string = ROOT_PARENT,
 ): VirtualRow[] {
   for (const child of children) {
     if (isFolder(child)) {
       const visible = query ? folderHasMatch(child, query) : true;
       if (!visible) continue;
-      out.push({ item: child, depth });
-      const childOpen = query ? true : openSet.has(child.path ?? child.name);
+      const path = child.path ?? child.name;
+      out.push({ item: child, depth, parentPath });
+      const childOpen = query ? true : openSet.has(path);
       if (childOpen)
         collectVisibleRows(
           child.children,
@@ -83,9 +104,17 @@ export function collectVisibleRows(
           out,
           depth + 1,
           closedHostParents,
+          path,
         );
     } else {
-      collectVisibleHostRows(child, query, closedHostParents, out, depth);
+      collectVisibleHostRows(
+        child,
+        query,
+        closedHostParents,
+        out,
+        depth,
+        parentPath,
+      );
     }
   }
   return out;
@@ -123,9 +152,6 @@ export function collectAllFolderPaths(
   return Array.from(paths).sort((a, b) => a.localeCompare(b));
 }
 
-/** Sentinel parent for rows sitting at the tree root (no folder). */
-export const ROOT_PARENT = "__root__";
-
 export function rowKey(item: Host | HostFolder): string {
   return isFolder(item)
     ? `folder:${item.path ?? item.name}`
diff --git a/src/ui/tests/sidebar/sidebar-tree-visible-rows.test.ts b/src/ui/tests/sidebar/sidebar-tree-visible-rows.test.ts
index e32411fe8..900196097 100644
--- a/src/ui/tests/sidebar/sidebar-tree-visible-rows.test.ts
+++ b/src/ui/tests/sidebar/sidebar-tree-visible-rows.test.ts
@@ -133,6 +133,34 @@ describe("collectVisibleRows with sub-host nesting", () => {
   });
 });
 
+describe("collectVisibleRows with group-by views", () => {
+  it("gives each occurrence of a multi-tag host a distinct parentPath", () => {
+    // Group-by-tags puts the same host under one synthetic folder per tag,
+    // so a host with two tags shows up twice in the tree with the same id.
+    const multiTagHost = host("9", "shared-box");
+    const tree: (Host | HostFolder)[] = [
+      {
+        name: "prod",
+        path: "__group__:tag:prod",
+        children: [multiTagHost],
+      },
+      {
+        name: "web",
+        path: "__group__:tag:web",
+        children: [multiTagHost],
+      },
+    ];
+    const rows = collectVisibleRows(
+      tree,
+      "",
+      new Set(["__group__:tag:prod", "__group__:tag:web"]),
+    );
+    const hostRows = rows.filter((r) => !isFolder(r.item));
+    expect(hostRows).toHaveLength(2);
+    expect(hostRows[0].parentPath).not.toBe(hostRows[1].parentPath);
+  });
+});
+
 describe("buildReorderRows", () => {
   it("keys folders by path and hosts by id", () => {
     const folder: HostFolder = {