diff --git a/neode-ui/src/components/MeshMap.vue b/neode-ui/src/components/MeshMap.vue
index f98a2245..2abc6943 100644
--- a/neode-ui/src/components/MeshMap.vue
+++ b/neode-ui/src/components/MeshMap.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { ref, onMounted, onUnmounted, watch, computed } from 'vue'
+import { ref, onMounted, onUnmounted, onActivated, onDeactivated, nextTick, watch, computed } from 'vue'
 import { useMeshStore } from '@/stores/mesh'
 import type { NodePosition } from '@/stores/mesh'
 import L from 'leaflet'
@@ -361,34 +361,76 @@ watch(
 
 let resizeObserver: ResizeObserver | null = null
 
-onMounted(() => {
+// Only-while-visible: the window resize listener and ResizeObserver follow
+// the Mesh tab's activate/deactivate lifecycle now that this component
+// survives a tab switch under KeepAlive (T-02-03/D-03 — Mesh.vue joined
+// KEEP_ALIVE_PATHS in 02-04). The Leaflet instance itself is never destroyed
+// or recreated by any of this: initMap()'s own `if (!mapContainer.value ||
+// map) return` guard already makes construction idempotent, so exactly one
+// map is built per session no matter how many times armMapVisibility() runs.
+// This only quiesces/repairs the listener + observer and re-tiles the map
+// around it, so a map laid out while off screen doesn't paint at a stale or
+// partial size on return.
+//
+// Called from BOTH onMounted and onActivated: onActivated is a documented
+// no-op outside a <KeepAlive> boundary (see Mesh.vue's own armMeshLive for
+// the same idiom), so a bare mount (a unit test, or any future non-KeepAlive
+// usage) must not silently skip this setup.
+function armMapVisibility() {
+  window.removeEventListener('resize', handleResize)
   window.addEventListener('resize', handleResize)
 
   if (mapContainer.value) {
-    resizeObserver = new ResizeObserver((entries) => {
-      const entry = entries[0]
-      if (!entry) return
-      const { height } = entry.contentRect
-      if (!map && height > 10) {
-        initMap()
-      } else if (map) {
-        try { map.invalidateSize() } catch { /* destroyed */ }
-      }
-    })
+    if (!resizeObserver) {
+      resizeObserver = new ResizeObserver((entries) => {
+        const entry = entries[0]
+        if (!entry) return
+        const { height } = entry.contentRect
+        if (!map && height > 10) {
+          initMap()
+        } else if (map) {
+          try { map.invalidateSize() } catch { /* destroyed */ }
+        }
+      })
+    }
     resizeObserver.observe(mapContainer.value)
   }
 
-  // Fallback init
+  // Fallback init for the very first mount (idempotent no-op once `map` is
+  // already set — mirrors initMap's own not-yet-laid-out retry loop).
   setTimeout(initMap, 300)
+
+  // A map laid out while the tab was off screen may have settled at a
+  // zero/partial size; re-tile it at its real size now that it's back on
+  // screen instead of showing an unsized or partially tiled canvas.
+  if (map) {
+    void nextTick(() => {
+      try { map?.invalidateSize() } catch { /* destroyed */ }
+    })
+  }
+}
+function disarmMapVisibility() {
+  window.removeEventListener('resize', handleResize)
+  if (resizeObserver) resizeObserver.disconnect()
+}
+
+// Vue fires onActivated immediately after onMounted on a KeepAlive-wrapped
+// component's first mount, which would otherwise double the fallback
+// setTimeout(initMap, 300) call on every fresh page load (harmless since
+// initMap is idempotent, but redundant). This flag lets onMounted's call
+// count as the first activation's arm, so onActivated only re-arms on a
+// genuine later reactivation, matching Mesh.vue's own meshFreshMount idiom.
+let mapMountFresh = true
+onActivated(() => {
+  if (mapMountFresh) { mapMountFresh = false; return }
+  armMapVisibility()
 })
+onMounted(() => armMapVisibility())
+onDeactivated(() => disarmMapVisibility())
 
 onUnmounted(() => {
-  window.removeEventListener('resize', handleResize)
+  disarmMapVisibility()
   stopSharing()
-  if (resizeObserver) {
-    resizeObserver.disconnect()
-    resizeObserver = null
-  }
   if (map) {
     map.remove()
     map = null
diff --git a/neode-ui/src/components/__tests__/meshMapLifecycle.test.ts b/neode-ui/src/components/__tests__/meshMapLifecycle.test.ts
new file mode 100644
index 00000000..3452dac8
--- /dev/null
+++ b/neode-ui/src/components/__tests__/meshMapLifecycle.test.ts
@@ -0,0 +1,166 @@
+// 02-05 Task 2: bounds MeshMap.vue's Leaflet instance across Mesh.vue's
+// activate/deactivate lifecycle (established in 02-04 — Mesh.vue joined
+// KEEP_ALIVE_PATHS). Kept in its own file rather than
+// src/views/__tests__/meshTabCache.test.ts because `vi.mock('@/stores/mesh')`
+// and `vi.mock('leaflet')` are hoisted file-wide and would otherwise clobber
+// that file's need for the REAL mesh/transport stores (mirrors the
+// MarketplaceRefresh.test.ts precedent set in 02-02 for the same class of
+// vi.mock-hoisting conflict — Rule 1/3 auto-fix, documented in
+// 02-05-SUMMARY.md).
+//
+// FLAGGED (see 02-05-SUMMARY.md): RESEARCH.md's premise that Mesh.vue owns a
+// live D3 force simulation does not hold for this codebase — a full grep for
+// `d3`/`forceSimulation`/`simulation` across neode-ui/src turns up nothing in
+// Mesh.vue's component tree (or MeshMap.vue's); the only D3 force simulation
+// in the codebase belongs to NetworkMap.vue (Federation.vue's graph, out of
+// this plan's scope). This file therefore only covers the Leaflet map's
+// activate/deactivate lifecycle — the D3-specific truths from the plan are
+// vacuously satisfied (there is nothing to leak).
+
+import { flushPromises, mount } from '@vue/test-utils'
+import { KeepAlive, defineComponent, h, ref } from 'vue'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import MeshMap from '../MeshMap.vue'
+
+const mapInstances: Array<{ invalidateSize: ReturnType<typeof vi.fn>; remove: ReturnType<typeof vi.fn> }> = []
+let resizeObserverInstances: Array<{ observe: ReturnType<typeof vi.fn>; disconnect: ReturnType<typeof vi.fn> }> = []
+
+vi.mock('@/stores/mesh', () => ({
+  useMeshStore: () => ({
+    nodePositions: new Map(),
+    federatedPositions: new Map(),
+    peers: [],
+    status: null,
+    deadmanStatus: null,
+    updateSelfPosition: vi.fn(),
+  }),
+}))
+
+vi.mock('leaflet', () => ({
+  default: {
+    map: vi.fn(() => {
+      const instance = { invalidateSize: vi.fn(), fitBounds: vi.fn(), remove: vi.fn(), setView: vi.fn() }
+      mapInstances.push(instance)
+      return instance
+    }),
+    tileLayer: vi.fn(() => ({ addTo: vi.fn() })),
+    layerGroup: vi.fn(() => ({ addTo: vi.fn(), clearLayers: vi.fn(), addLayer: vi.fn() })),
+    divIcon: vi.fn((opts: unknown) => opts),
+    marker: vi.fn(() => ({ bindPopup: vi.fn() })),
+    polyline: vi.fn(() => ({})),
+    latLngBounds: vi.fn(() => ({})),
+  },
+}))
+
+const Other = defineComponent({ name: 'Other', render: () => h('div', 'other') })
+
+function mountMapHost() {
+  const Host = defineComponent({
+    setup() {
+      const show = ref(true)
+      return { show }
+    },
+    render() {
+      return h(KeepAlive, null, () =>
+        this.show ? h(MeshMap, { key: 'map' }) : h(Other, { key: 'other' }),
+      )
+    },
+  })
+  return mount(Host)
+}
+
+async function toggleTab(wrapper: ReturnType<typeof mountMapHost>, show: boolean) {
+  ;(wrapper.vm as unknown as { show: boolean }).show = show
+  await wrapper.vm.$nextTick()
+}
+
+describe('Mesh graphics lifecycle (Task 2): Leaflet map (MeshMap.vue)', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+    mapInstances.length = 0
+    resizeObserverInstances = []
+    vi.stubGlobal('ResizeObserver', vi.fn(() => {
+      const inst = { observe: vi.fn(), disconnect: vi.fn(), unobserve: vi.fn() }
+      resizeObserverInstances.push(inst)
+      return inst
+    }))
+    vi.spyOn(Element.prototype, 'getBoundingClientRect').mockReturnValue({
+      height: 200, width: 200, top: 0, left: 0, right: 0, bottom: 0, x: 0, y: 0, toJSON: () => undefined,
+    } as DOMRect)
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+    vi.restoreAllMocks()
+    vi.unstubAllGlobals()
+  })
+
+  it('entering and leaving the tab three times constructs exactly one map instance', async () => {
+    const wrapper = mountMapHost()
+    await flushPromises()
+    vi.advanceTimersByTime(300) // the onMounted-arm's fallback initMap()
+    await flushPromises()
+    expect(mapInstances.length).toBe(1)
+
+    for (let i = 0; i < 3; i++) {
+      await toggleTab(wrapper, false)
+      await toggleTab(wrapper, true)
+      await flushPromises()
+    }
+    expect(mapInstances.length).toBe(1)
+
+    wrapper.unmount()
+  })
+
+  it('reactivating calls the Leaflet map size-invalidation so a map laid out off screen re-tiles at its real size', async () => {
+    const wrapper = mountMapHost()
+    await flushPromises()
+    vi.advanceTimersByTime(300)
+    await flushPromises()
+    const instance = mapInstances[0]!
+    instance.invalidateSize.mockClear()
+
+    await toggleTab(wrapper, false)
+    await toggleTab(wrapper, true)
+    await flushPromises()
+
+    expect(instance.invalidateSize).toHaveBeenCalled()
+    wrapper.unmount()
+  })
+
+  it('a window resize listener is removed on deactivate and re-added exactly once on activate', async () => {
+    const addSpy = vi.spyOn(window, 'addEventListener')
+    const removeSpy = vi.spyOn(window, 'removeEventListener')
+    const wrapper = mountMapHost()
+    await flushPromises()
+    // armMapVisibility's own idempotent idiom (remove-then-add) means mount
+    // itself issues one defensive remove alongside the one add — baseline
+    // both counts here rather than assuming remove starts at zero.
+    const addCountAtMount = addSpy.mock.calls.filter((c) => c[0] === 'resize').length
+    const removeCountAtMount = removeSpy.mock.calls.filter((c) => c[0] === 'resize').length
+    expect(addCountAtMount).toBe(1)
+
+    await toggleTab(wrapper, false)
+    expect(removeSpy.mock.calls.filter((c) => c[0] === 'resize').length).toBe(removeCountAtMount + 1)
+
+    await toggleTab(wrapper, true)
+    expect(addSpy.mock.calls.filter((c) => c[0] === 'resize').length).toBe(addCountAtMount + 1) // once more, not twice
+
+    wrapper.unmount()
+  })
+
+  it('deactivating disconnects the ResizeObserver; reactivating re-observes the container', async () => {
+    const wrapper = mountMapHost()
+    await flushPromises()
+    const inst = resizeObserverInstances[0]!
+    expect(inst.observe).toHaveBeenCalledTimes(1)
+
+    await toggleTab(wrapper, false)
+    expect(inst.disconnect).toHaveBeenCalledTimes(1)
+
+    await toggleTab(wrapper, true)
+    expect(inst.observe).toHaveBeenCalledTimes(2)
+
+    wrapper.unmount()
+  })
+})