diff --git a/public/live.js b/public/live.js
index f44fb054..4b79aac0 100644
--- a/public/live.js
+++ b/public/live.js
@@ -2909,7 +2909,12 @@
     if (nodeFilterKeys.length > 0) {
       if (clearBtn) clearBtn.style.display = '';
       if (countEl) { countEl.textContent = `Showing ${nodeFilterShown} of ${nodeFilterTotal}`; countEl.classList.remove('hidden'); }
-      if (input && input.value !== nodeFilterKeys.join(', ')) input.value = nodeFilterKeys.join(', ');
+      // Never overwrite the field while the user is in it: this also runs from the
+      // debounced typing handler (which commits the trimmed value) and from every
+      // matching packet, and a picked suggestion shows the name while the key is
+      // the pubkey. Compare trimmed so a stray space alone is no reason to write.
+      const userIsEditing = document.activeElement === input;
+      if (input && !userIsEditing && input.value.trim() !== nodeFilterKeys.join(', ')) input.value = nodeFilterKeys.join(', ');
     } else {
       if (clearBtn) clearBtn.style.display = 'none';
       if (countEl) countEl.classList.add('hidden');
diff --git a/test-live.js b/test-live.js
index 5df12ef3..fe6cb601 100644
--- a/test-live.js
+++ b/test-live.js
@@ -1027,6 +1027,55 @@ console.log('\n=== live.js: node filter ===');
     setFilter([]);
     assert.strictEqual(ctx.localStorage.getItem('live-node-filter'), '');
   });
+
+  // updateNodeFilterUI writes the filter keys into the input. It runs from the
+  // debounced typing handler (which commits the trimmed value) and from every
+  // matching live packet, so it must not overwrite what the user is typing.
+  function withFilterInput(value, focused, fn) {
+    const input = { value };
+    const origGet = ctx.document.getElementById;
+    const origActive = ctx.document.activeElement;
+    ctx.document.getElementById = (id) => (id === 'liveNodeFilterInput' ? input : null);
+    ctx.document.activeElement = focused ? input : null;
+    try { fn(input); } finally {
+      ctx.document.getElementById = origGet;
+      ctx.document.activeElement = origActive;
+      ctx.window._liveSetNodeFilter([]);
+    }
+  }
+
+  // Typing "Dan's Local" slowly: the debounce commits "Dan's"; writing that
+  // back dropped the space and the next word was glued on ("Dan'sLocal").
+  test('node filter keeps a trailing space the user is typing', () => {
+    withFilterInput("Dan's ", true, (input) => {
+      ctx.window._liveSetNodeFilter(["Dan's"]);
+      assert.strictEqual(input.value, "Dan's ", 'input rewritten while typing');
+    });
+  });
+
+  // A matching packet re-renders the filter UI while the user has typed a
+  // character the 200 ms debounce has not committed yet ("ab12" -> "ab123").
+  // The same guard keeps a picked suggestion's name instead of its pubkey.
+  test('node filter does not overwrite a focused input that differs', () => {
+    withFilterInput('ab123', true, (input) => {
+      ctx.window._liveSetNodeFilter(['ab12']);
+      assert.strictEqual(input.value, 'ab123', 'focused input overwritten');
+    });
+  });
+
+  test('node filter writes a different key into an unfocused input', () => {
+    withFilterInput('Dan', false, (input) => {
+      ctx.window._liveSetNodeFilter(['abcd1234', 'ef012345']);
+      assert.strictEqual(input.value, 'abcd1234, ef012345');
+    });
+  });
+
+  test('node filter leaves an unfocused input that differs only by whitespace', () => {
+    withFilterInput('  ab12 ', false, (input) => {
+      ctx.window._liveSetNodeFilter(['ab12']);
+      assert.strictEqual(input.value, '  ab12 ');
+    });
+  });
 }
 
 // ===== Clickable paths (M2 — #771) =====