diff --git a/src/main.cpp b/src/main.cpp
index aa6fc1d3..5606e957 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -32,6 +32,7 @@ int main(int argc, char ** argv)
     darkPalette.setColor(QPalette::ToolTipBase, Theme::white);
     darkPalette.setColor(QPalette::ToolTipText, Theme::white);
     darkPalette.setColor(QPalette::Text, Theme::white);
+    darkPalette.setColor(QPalette::Disabled, QPalette::Text, Theme::black);
     darkPalette.setColor(QPalette::Button, QColor(53,53,53));
     darkPalette.setColor(QPalette::ButtonText, Theme::white);
     darkPalette.setColor(QPalette::BrightText, Theme::red);
diff --git a/src/skeletondocument.cpp b/src/skeletondocument.cpp
index da24ed7d..a7235880 100644
--- a/src/skeletondocument.cpp
+++ b/src/skeletondocument.cpp
@@ -14,7 +14,8 @@ unsigned long SkeletonDocument::m_maxSnapshot = 1000;
 SkeletonDocument::SkeletonDocument() :
     m_resultMeshIsObsolete(false),
     m_resultMesh(nullptr),
-    m_meshGenerator(nullptr)
+    m_meshGenerator(nullptr),
+    m_batchChangeRefCount(0)
 {
 }
 
@@ -754,9 +755,24 @@ void SkeletonDocument::meshReady()
     }
 }
 
+void SkeletonDocument::batchChangeBegin()
+{
+    m_batchChangeRefCount++;
+}
+
+void SkeletonDocument::batchChangeEnd()
+{
+    m_batchChangeRefCount--;
+    if (0 == m_batchChangeRefCount) {
+        if (m_resultMeshIsObsolete) {
+            generateMesh();
+        }
+    }
+}
+
 void SkeletonDocument::generateMesh()
 {
-    if (nullptr != m_meshGenerator) {
+    if (nullptr != m_meshGenerator || m_batchChangeRefCount > 0) {
         m_resultMeshIsObsolete = true;
         return;
     }
@@ -867,3 +883,15 @@ void SkeletonDocument::paste()
         addFromSnapshot(snapshot);
     }
 }
+
+bool SkeletonDocument::hasPastableContentInClipboard() const
+{
+    const QClipboard *clipboard = QApplication::clipboard();
+    const QMimeData *mimeData = clipboard->mimeData();
+    if (mimeData->hasText()) {
+        if (-1 != mimeData->text().left(1000).indexOf("partIdList"))
+            return true;
+    }
+    return false;
+}
+
diff --git a/src/skeletondocument.h b/src/skeletondocument.h
index 90e56633..b7d0a4b3 100644
--- a/src/skeletondocument.h
+++ b/src/skeletondocument.h
@@ -106,6 +106,13 @@ public:
     }
 };
 
+enum class SkeletonProfile
+{
+    Unknown = 0,
+    Main,
+    Side
+};
+
 class SkeletonHistoryItem
 {
 public:
@@ -121,13 +128,6 @@ enum class SkeletonDocumentEditMode
     ZoomOut
 };
 
-enum class SkeletonProfile
-{
-    Unknown = 0,
-    Main,
-    Side
-};
-
 class SkeletonDocument : public QObject
 {
     Q_OBJECT
@@ -170,6 +170,7 @@ public:
     Mesh *takeResultMesh();
     QImage preview;
     void updateTurnaround(const QImage &image);
+    bool hasPastableContentInClipboard() const;
 public slots:
     void removeNode(QUuid nodeId);
     void removeEdge(QUuid edgeId);
@@ -193,6 +194,8 @@ public slots:
     void undo();
     void redo();
     void paste();
+    void batchChangeBegin();
+    void batchChangeEnd();
 private:
     void splitPartByNode(std::vector<std::vector<QUuid>> *groups, QUuid nodeId);
     void joinNodeAndNeiborsToGroup(std::vector<QUuid> *group, QUuid nodeId, std::set<QUuid> *visitMap, QUuid noUseEdgeId=QUuid());
@@ -205,6 +208,7 @@ private:
     static unsigned long m_maxSnapshot;
     std::deque<SkeletonHistoryItem> m_undoItems;
     std::deque<SkeletonHistoryItem> m_redoItems;
+    int m_batchChangeRefCount;
 };
 
 #endif
diff --git a/src/skeletondocumentwindow.cpp b/src/skeletondocumentwindow.cpp
index 4bafbd60..16deac23 100644
--- a/src/skeletondocumentwindow.cpp
+++ b/src/skeletondocumentwindow.cpp
@@ -195,6 +195,8 @@ SkeletonDocumentWindow::SkeletonDocumentWindow() :
     connect(graphicsWidget, &SkeletonGraphicsWidget::redo, m_document, &SkeletonDocument::redo);
     connect(graphicsWidget, &SkeletonGraphicsWidget::paste, m_document, &SkeletonDocument::paste);
     connect(graphicsWidget, &SkeletonGraphicsWidget::changeTurnaround, this, &SkeletonDocumentWindow::changeTurnaround);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::batchChangeBegin, m_document, &SkeletonDocument::batchChangeBegin);
+    connect(graphicsWidget, &SkeletonGraphicsWidget::batchChangeEnd, m_document, &SkeletonDocument::batchChangeEnd);
     
     connect(m_document, &SkeletonDocument::nodeAdded, graphicsWidget, &SkeletonGraphicsWidget::nodeAdded);
     connect(m_document, &SkeletonDocument::nodeRemoved, graphicsWidget, &SkeletonGraphicsWidget::nodeRemoved);
diff --git a/src/skeletongraphicswidget.cpp b/src/skeletongraphicswidget.cpp
index ac789e6e..6ee38c71 100644
--- a/src/skeletongraphicswidget.cpp
+++ b/src/skeletongraphicswidget.cpp
@@ -102,10 +102,23 @@ void SkeletonGraphicsWidget::showContextMenu(const QPoint &pos)
     
     QAction pasteAction("Paste", this);
     connect(&pasteAction, &QAction::triggered, m_document, &SkeletonDocument::paste);
+    pasteAction.setEnabled(m_document->hasPastableContentInClipboard());
     contextMenu.addAction(&pasteAction);
     
     contextMenu.addSeparator();
     
+    QAction flipHorizontallyAction("H Flip", this);
+    connect(&flipHorizontallyAction, &QAction::triggered, this, &SkeletonGraphicsWidget::flipHorizontally);
+    flipHorizontallyAction.setEnabled(!m_rangeSelectionSet.empty());
+    contextMenu.addAction(&flipHorizontallyAction);
+    
+    QAction flipVerticallyAction("V Flip", this);
+    connect(&flipVerticallyAction, &QAction::triggered, this, &SkeletonGraphicsWidget::flipVertically);
+    flipVerticallyAction.setEnabled(!m_rangeSelectionSet.empty());
+    contextMenu.addAction(&flipVerticallyAction);
+    
+    contextMenu.addSeparator();
+    
     QAction selectAllAction("Select All", this);
     connect(&selectAllAction, &QAction::triggered, this, &SkeletonGraphicsWidget::selectAll);
     selectAllAction.setEnabled(!nodeItemMap.empty());
@@ -123,18 +136,6 @@ void SkeletonGraphicsWidget::showContextMenu(const QPoint &pos)
     
     contextMenu.addSeparator();
     
-    QAction addMirrorAction("Mirror", this);
-    connect(&addMirrorAction, &QAction::triggered, this, &SkeletonGraphicsWidget::addMirror);
-    addMirrorAction.setEnabled(readSkeletonNodeAndAnyEdgeOfNodeFromRangeSelection(nullptr, nullptr));
-    contextMenu.addAction(&addMirrorAction);
-    
-    QAction deleteMirrorAction("Delete Mirror", this);
-    connect(&deleteMirrorAction, &QAction::triggered, this, &SkeletonGraphicsWidget::deleteMirror);
-    deleteMirrorAction.setEnabled(readSkeletonNodeAndAnyEdgeOfNodeFromRangeSelection(nullptr, nullptr));
-    contextMenu.addAction(&deleteMirrorAction);
-    
-    contextMenu.addSeparator();
-    
     QAction changeTurnaroundAction("Change Turnaround..", this);
     connect(&changeTurnaroundAction, &QAction::triggered, [=]() {
         emit changeTurnaround();
@@ -425,11 +426,7 @@ bool SkeletonGraphicsWidget::wheel(QWheelEvent *event)
             readMergedSkeletonNodeSetFromRangeSelection(&nodeItems);
             float unifiedDelta = sceneRadiusToUnified(delta);
             if (QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ControlModifier)) {
-                QVector2D center;
-                for (const auto &nodeItem: nodeItems) {
-                    center += QVector2D(nodeItem->origin());
-                }
-                center /= nodeItems.size();
+                QVector2D center = centerOfNodeItemSet(nodeItems);
                 for (const auto &nodeItem: nodeItems) {
                     QVector2D origin = QVector2D(nodeItem->origin());
                     QVector2D ray = (center - origin) * 0.01 * delta;
@@ -459,6 +456,50 @@ bool SkeletonGraphicsWidget::wheel(QWheelEvent *event)
     return false;
 }
 
+QVector2D SkeletonGraphicsWidget::centerOfNodeItemSet(const std::set<SkeletonGraphicsNodeItem *> &set)
+{
+    QVector2D center;
+    for (const auto &nodeItem: set) {
+        center += QVector2D(nodeItem->origin());
+    }
+    center /= set.size();
+    return center;
+}
+
+void SkeletonGraphicsWidget::flipHorizontally()
+{
+    std::set<SkeletonGraphicsNodeItem *> nodeItems;
+    readMergedSkeletonNodeSetFromRangeSelection(&nodeItems);
+    if (nodeItems.empty())
+        return;
+    QVector2D center = centerOfNodeItemSet(nodeItems);
+    for (const auto &nodeItem: nodeItems) {
+        QPointF origin = nodeItem->origin();
+        float offset = origin.x() - center.x();
+        float unifiedOffset = -sceneRadiusToUnified(offset * 2);
+        if (SkeletonProfile::Main == nodeItem->profile()) {
+            emit moveNodeBy(nodeItem->id(), unifiedOffset, 0, 0);
+        } else {
+            emit moveNodeBy(nodeItem->id(), 0, 0, unifiedOffset);
+        }
+    }
+}
+
+void SkeletonGraphicsWidget::flipVertically()
+{
+    std::set<SkeletonGraphicsNodeItem *> nodeItems;
+    readMergedSkeletonNodeSetFromRangeSelection(&nodeItems);
+    if (nodeItems.empty())
+        return;
+    QVector2D center = centerOfNodeItemSet(nodeItems);
+    for (const auto &nodeItem: nodeItems) {
+        QPointF origin = nodeItem->origin();
+        float offset = origin.y() - center.y();
+        float unifiedOffset = -sceneRadiusToUnified(offset * 2);
+        emit moveNodeBy(nodeItem->id(), 0, unifiedOffset, 0);
+    }
+}
+
 bool SkeletonGraphicsWidget::mouseRelease(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton) {
@@ -619,6 +660,7 @@ bool SkeletonGraphicsWidget::mouseDoubleClick(QMouseEvent *event)
 void SkeletonGraphicsWidget::deleteSelected()
 {
     if (!m_rangeSelectionSet.empty()) {
+        emit batchChangeBegin();
         std::set<QUuid> nodeIdSet;
         std::set<QUuid> edgeIdSet;
         readSkeletonNodeAndEdgeIdSetFromRangeSelection(&nodeIdSet, &edgeIdSet);
@@ -628,6 +670,7 @@ void SkeletonGraphicsWidget::deleteSelected()
         for (const auto &id: nodeIdSet) {
             emit removeNode(id);
         }
+        emit batchChangeEnd();
     }
 }
 
@@ -1094,3 +1137,6 @@ void SkeletonGraphicsWidget::copy()
     QClipboard *clipboard = QApplication::clipboard();
     clipboard->setText(snapshotXml);
 }
+
+
+
diff --git a/src/skeletongraphicswidget.h b/src/skeletongraphicswidget.h
index bddca0a3..f54f9967 100644
--- a/src/skeletongraphicswidget.h
+++ b/src/skeletongraphicswidget.h
@@ -264,8 +264,8 @@ signals:
     void redo();
     void paste();
     void changeTurnaround();
-    void addMirror();
-    void deleteMirror();
+    void batchChangeBegin();
+    void batchChangeEnd();
 public:
     SkeletonGraphicsWidget(const SkeletonDocument *document);
     std::map<QUuid, std::pair<SkeletonGraphicsNodeItem *, SkeletonGraphicsNodeItem *>> nodeItemMap;
@@ -308,6 +308,8 @@ public slots:
     void selectPartAll();
     void cut();
     void copy();
+    void flipHorizontally();
+    void flipVertically();
 private slots:
     void turnaroundImageReady();
 private:
@@ -321,6 +323,7 @@ private:
     void checkRangeSelection();
     void clearRangeSelection();
     void removeItem(QGraphicsItem *item);
+    QVector2D centerOfNodeItemSet(const std::set<SkeletonGraphicsNodeItem *> &set);
 private:
     QGraphicsPixmapItem *m_backgroundItem;
     const SkeletonDocument *m_document;
diff --git a/src/skeletonsnapshot.h b/src/skeletonsnapshot.h
index b94974dc..f6e5b850 100644
--- a/src/skeletonsnapshot.h
+++ b/src/skeletonsnapshot.h
@@ -13,6 +13,8 @@ public:
     std::map<QString, std::map<QString, QString>> nodes;
     std::map<QString, std::map<QString, QString>> edges;
     std::map<QString, std::map<QString, QString>> parts;
+    std::map<QString, std::map<QString, QString>> mirrors;
+    std::map<QString, std::map<QString, QString>> trivialMarkers;
     std::vector<QString> partIdList;
 public:
     SkeletonSnapshot();