diff --git a/tools/chatgui/CMakeLists.txt b/tools/chatgui/CMakeLists.txt
index 88189c55..10ebc9ff 100644
--- a/tools/chatgui/CMakeLists.txt
+++ b/tools/chatgui/CMakeLists.txt
@@ -675,6 +675,10 @@ add_executable(test_stream_view tests/test_stream_view.cpp src/streamplayer_wind
     transport/miniaudio_impl.c transport/audio_diagnostics.cpp)
 target_include_directories(test_stream_view PRIVATE ${UTUN_INCLUDE_DIRS} ${FFMPEG_INCLUDE_DIRS})
 target_link_libraries(test_stream_view PRIVATE ${QT_LIBS} ${QT_TEST_LIB} utun_voice utun pthread ${CMAKE_DL_LIBS} ${FFMPEG_TARGET} ${FFMPEG_LIBRARIES})
+if(GUI_CAPTURE_ENABLED)
+    target_compile_definitions(test_stream_view PRIVATE HAVE_STREAM_CAPTURE)
+    target_link_libraries(test_stream_view PRIVATE Qt6::Multimedia Qt6::MultimediaWidgets)
+endif()
 if(FFMPEG_FOUND)
     target_compile_definitions(test_stream_view PRIVATE HAVE_FFMPEG)
 endif()
diff --git a/tools/chatgui/tests/test_stream_view.cpp b/tools/chatgui/tests/test_stream_view.cpp
index 564569c1..5e3c8fd6 100644
--- a/tools/chatgui/tests/test_stream_view.cpp
+++ b/tools/chatgui/tests/test_stream_view.cpp
@@ -13,6 +13,12 @@
 #include <QSlider>
 #include <QPainter>
 #include <QWheelEvent>
+#ifdef HAVE_STREAM_CAPTURE
+#include <QVideoWidget>
+#include <QVideoSink>
+#include <QVideoFrame>
+#include <QVideoFrameFormat>
+#endif
 #include <atomic>
 #include <cmath>
 #include <chrono>
@@ -444,7 +450,7 @@ private slots:
             QJsonArray sources;
             for (int i = 0; i < count; ++i) sources.append(QJsonObject{
                 {"id", QString::number(inst->node_id ^ static_cast<uint64_t>(i))},
-                {"epoch", QString::number(epoch, 16)}, {"name", QStringLiteral("Source %1").arg(i)}, {"self", i == 0 ? 1 : 0}});
+                {"epoch", QString::number(epoch, 16)}, {"name", QStringLiteral("Source %1").arg(i)}, {"self", 0}});
             QByteArray bytes(9, '\0'); stream_write_be(reinterpret_cast<uint8_t*>(bytes.data()), group, 8); bytes[8] = valid;
             bytes += QJsonDocument(sources).toJson(QJsonDocument::Compact);
             grid.onSources(reinterpret_cast<const uint8_t*>(bytes.constData()), bytes.size());
@@ -463,7 +469,10 @@ private slots:
         QCOMPARE(stream_publish_finish(publisher), STREAM_OK); stream_close(publisher); publisher = nullptr;
         QCOMPARE(stream_publish_open(inst, group, nullptr, &publisher), STREAM_OK);
         stream_info info{}; QCOMPARE(stream_get_info(publisher, &info), STREAM_OK); epoch = info.descriptor.source_epoch;
+        QTest::mouseClick(first->findChild<VideoRenderWidget*>(), Qt::LeftButton);
+        QTRY_COMPARE(grid.focusedSource(), inst->node_id);
         snapshot(1); QVERIFY(first.isNull()); QCOMPARE(grid.tileCount(), 1);
+        QCOMPARE(grid.focusedSource(), uint64_t(0)); QVERIFY(!grid.isFullScreen());
         snapshot(0); QTRY_COMPARE_WITH_TIMEOUT(grid.tileCount(), 0, 3000);
         QVERIFY(grid.isVisible()); QCOMPARE(grid.gridSide(), 0);
         snapshot(1); QCOMPARE(grid.tileCount(), 1);
@@ -474,6 +483,61 @@ private slots:
 #endif
     }
 
+    void gridLocalPreviewAndTileNavigation() {
+#if defined(TEST_NULL_AUDIO) && defined(HAVE_STREAM_CAPTURE)
+        StreamGridWindow grid(group); grid.show(); grid.activateWindow();
+        const auto own = inst->node_id ^ uint64_t(1);
+        auto snapshot = [&](bool remote) {
+            QJsonArray sources{QJsonObject{{"id", QString::number(own)}, {"epoch", QString::number(epoch, 16)},
+                {"name", "Own preview"}, {"self", 1}}};
+            if (remote) sources.append(QJsonObject{{"id", QString::number(inst->node_id)}, {"epoch", QString::number(epoch, 16)},
+                {"name", "Remote fixture"}, {"self", 0}});
+            QByteArray bytes(9, '\0'); stream_write_be(reinterpret_cast<uint8_t*>(bytes.data()), group, 8); bytes[8] = 1;
+            bytes += QJsonDocument(sources).toJson(QJsonDocument::Compact);
+            grid.onSources(reinterpret_cast<const uint8_t*>(bytes.constData()), bytes.size());
+        };
+        snapshot(false);
+        auto* ownTile = grid.findChild<QWidget*>(QStringLiteral("streamPreview_%1").arg(own)); QVERIFY(ownTile);
+        auto* preview = ownTile->findChild<QVideoWidget*>(); QVERIFY(preview);
+        QVERIFY(grid.findChildren<StreamPlayerWindow*>().isEmpty()); QVERIFY(ownTile->findChildren<QSlider*>().isEmpty());
+        stream_info info{}; QTest::qWait(30);
+        QCOMPARE(stream_get_info(publisher, &info), STREAM_OK); QCOMPARE(info.owners, 1u);
+        QVideoFrame frame(QVideoFrameFormat(QSize(16, 16), QVideoFrameFormat::Format_BGRA8888));
+        QVERIFY(frame.map(QVideoFrame::WriteOnly)); memset(frame.bits(0), 0xff, frame.mappedBytes(0)); frame.unmap();
+        frame.setStartTime(123000);
+        grid.setLocalPreview(group, QVariant::fromValue(frame));
+        QCOMPARE(preview->videoSink()->videoFrame().startTime(), qint64(123000));
+        grid.setLocalPreview(group ^ 1, QVariant()); QVERIFY(preview->videoSink()->videoFrame().isValid());
+        grid.setLocalPreview(group, QVariant()); QVERIFY(!preview->videoSink()->videoFrame().isValid());
+        grid.setLocalPreview(group, QVariant::fromValue(frame));
+        QSignalSpy manage(&grid, &StreamGridWindow::publishRequested);
+        QTest::mouseClick(preview, Qt::LeftButton); QTRY_COMPARE(manage.count(), 1);
+        QCOMPARE(manage.at(0).at(0).toULongLong(), group); QCOMPARE(grid.focusedSource(), uint64_t(0));
+        snapshot(true);
+        QPointer<StreamPlayerWindow> remote = grid.findChild<StreamPlayerWindow*>();
+        QVERIFY(remote); auto* video = remote->findChild<VideoRenderWidget*>(); QVERIFY(video);
+        QTRY_VERIFY(stream_get_info(publisher, &info) == STREAM_OK && info.owners == 2);
+        QTest::mouseClick(video, Qt::LeftButton);
+        QTRY_COMPARE(grid.focusedSource(), inst->node_id); QVERIFY(grid.isFullScreen()); QVERIFY(ownTile->isHidden());
+        auto* volume = remote->findChild<QSlider*>(); QVERIFY(volume); volume->setFocus();
+        QTest::keyClick(volume, Qt::Key_Escape);
+        QTRY_COMPARE(grid.focusedSource(), uint64_t(0));
+        QVERIFY(!grid.isFullScreen()); QVERIFY(remote->isVisible()); QVERIFY(ownTile->isVisible());
+        QCOMPARE(grid.findChild<StreamPlayerWindow*>(), remote.data());
+        QCOMPARE(stream_get_info(publisher, &info), STREAM_OK); QCOMPARE(info.owners, 2u);
+        QTest::mouseClick(video, Qt::LeftButton); QTRY_COMPARE(grid.focusedSource(), inst->node_id);
+        QTest::mouseClick(video, Qt::LeftButton); QTRY_COMPARE(grid.focusedSource(), uint64_t(0));
+        video->setFrame(coordinateFrame()); zoomVideo(*video, 12000, video->rect().center());
+        dragVideo(*video, video->rect().center(), video->rect().center() + QPoint(40, 20));
+        QTest::qWait(20); QCOMPARE(grid.focusedSource(), uint64_t(0)); // Pan не считается кликом.
+        grid.close(); QVERIFY(remote.isNull());
+        QTRY_VERIFY(stream_get_info(publisher, &info) == STREAM_OK && info.owners == 1);
+        DEBUG_INFO(DEBUG_CATEGORY_STREAM, "fixture multiview local preview: reader=0 audio=0; click/Esc/drag preserved remote owner");
+#else
+        QSKIP("Direct preview fixture requires Qt Multimedia and null audio");
+#endif
+    }
+
     void realH264RenderingAndClose() {
 #ifdef HAVE_FFMPEG
         /* Фикстура протокола выше содержит фиктивный H264; реальный decoder получает отдельную эпоху. */