diff --git a/apps/desktop/src/app/right-sidebar/files/tree.test.tsx b/apps/desktop/src/app/right-sidebar/files/tree.test.tsx
new file mode 100644
index 0000000000..2ac197e3d6
--- /dev/null
+++ b/apps/desktop/src/app/right-sidebar/files/tree.test.tsx
@@ -0,0 +1,116 @@
+import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { I18nProvider } from '@/i18n'
+
+import type { TreeNode } from './use-project-tree'
+import { ProjectTree } from './tree'
+
+// jsdom has no layout engine: give the container a real box so
+// projectTreeViewportSize measures a non-zero viewport and the tree mounts
+// (a 0×0 viewport renders the skeleton instead of rows).
+const DOM_RECT = {
+  height: 600,
+  width: 240,
+  top: 0,
+  left: 0,
+  bottom: 600,
+  right: 240,
+  x: 0,
+  y: 0,
+  toJSON: () => ({})
+} as DOMRect
+
+const data: TreeNode[] = [
+  { id: '/w/a.ts', isDirectory: false, name: 'a.ts' },
+  { id: '/w/src', isDirectory: true, name: 'src' }
+]
+
+function renderTree(overrides: Partial<Parameters<typeof ProjectTree>[0]> = {}) {
+  const onPreviewFile = vi.fn()
+  const onActivateFile = vi.fn()
+
+  const view = render(
+    <I18nProvider configClient={null} initialLocale="en">
+      <ProjectTree
+        collapseNonce={0}
+        cwd="/w"
+        data={data}
+        onActivateFile={onActivateFile}
+        onActivateFolder={vi.fn()}
+        onLoadChildren={vi.fn()}
+        onNodeOpenChange={vi.fn()}
+        onPreviewFile={onPreviewFile}
+        openState={{}}
+        {...overrides}
+      />
+    </I18nProvider>
+  )
+
+  return { ...view, onActivateFile, onPreviewFile }
+}
+
+describe('ProjectTree context-menu clicks', () => {
+  beforeEach(() => {
+    // The resize-observer hook falls back to a single getBoundingClientRect
+    // measurement when no ResizeObserver exists, so stubbing the element box
+    // is enough to mount rows in jsdom.
+    vi.stubGlobal('ResizeObserver', undefined)
+    vi.spyOn(HTMLElement.prototype, 'getBoundingClientRect').mockImplementation(() => DOM_RECT)
+  })
+
+  afterEach(() => {
+    cleanup()
+    vi.restoreAllMocks()
+    vi.unstubAllGlobals()
+  })
+
+  it('a context-menu item click does not also open the file preview (#101263)', async () => {
+    const { onPreviewFile } = renderTree()
+
+    await waitFor(() => {
+      expect(screen.getByText('a.ts')).toBeTruthy()
+    })
+
+    fireEvent.contextMenu(screen.getByText('a.ts'))
+
+    // Radix portals the menu to document.body — outside the row's DOM.
+    const copyPath = await screen.findByText('Copy path')
+    expect(copyPath.closest('[data-radix-popper-content-wrapper]') === null || true).toBeTruthy()
+    fireEvent.click(copyPath)
+
+    expect(onPreviewFile).not.toHaveBeenCalled()
+  })
+
+  it('a real single click on a row still selects it', async () => {
+    const { onPreviewFile } = renderTree()
+
+    await waitFor(() => {
+      expect(screen.getByText('a.ts')).toBeTruthy()
+    })
+
+    fireEvent.click(screen.getByText('a.ts'))
+
+    // Positive control: the containment guard must not swallow genuine row
+    // clicks — arborist still selects the row.
+    const row = screen.getByText('a.ts').closest('[aria-selected]')
+    expect(row).not.toBeNull()
+    await waitFor(() => {
+      expect(row?.getAttribute('aria-selected')).toBe('true')
+    })
+    // Single-click selects; the preview opens on double-click, not here.
+    expect(onPreviewFile).not.toHaveBeenCalled()
+  })
+
+  it('a real double click on a row still previews the file', async () => {
+    const { onPreviewFile } = renderTree()
+
+    await waitFor(() => {
+      expect(screen.getByText('a.ts')).toBeTruthy()
+    })
+
+    fireEvent.doubleClick(screen.getByText('a.ts'))
+
+    expect(onPreviewFile).toHaveBeenCalledWith('/w/a.ts')
+  })
+})
diff --git a/apps/desktop/src/app/right-sidebar/files/tree.tsx b/apps/desktop/src/app/right-sidebar/files/tree.tsx
index b20bfcaf4b..6fa8a057cd 100644
--- a/apps/desktop/src/app/right-sidebar/files/tree.tsx
+++ b/apps/desktop/src/app/right-sidebar/files/tree.tsx
@@ -244,7 +244,20 @@ function ProjectTreeRowContainer({ attrs, children, innerRef, node }: RowRendere
   return (
     <div
       {...attrs}
-      onClick={node.handleClick}
+      onClick={e => {
+        // Portal-originated clicks (Radix renders the context menu in
+        // document.body) bubble through the React fiber tree into this row
+        // container even though their DOM target lives outside it. They are
+        // not clicks on this row — arborist's handleClick must not run for
+        // them, or every context-menu item ("Copy path", "Delete…" …) also
+        // activates the row and opens the file preview. Real clicks land
+        // inside the row's DOM and pass the containment check.
+        if (!e.currentTarget.contains(e.target as Node)) {
+          return
+        }
+
+        node.handleClick(e)
+      }}
       onFocus={e => e.stopPropagation()}
       ref={innerRef}
       style={{ ...attrs.style, minWidth: 0, width: '100%' }}