diff --git a/src/data/extra/web/js/markdownit.js b/src/data/extra/web/js/markdownit.js
index c24d3993..a323ea64 100644
--- a/src/data/extra/web/js/markdownit.js
+++ b/src/data/extra/web/js/markdownit.js
@@ -293,7 +293,7 @@ class MarkdownIt extends VxWorker {
         }
         // Add 1x1 transparent GIF image at the end to monitor the load process.
         return '<img src="data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==" onload="'
-               + p_cbStr + ' this.parentNode.removeChild(this);">';
+               + p_cbStr + ' try { this.parentNode.removeChild(this); } catch(error) { console.log(error); }">';
     }
 
     addLangsToSkipHighlight(p_langs) {
diff --git a/src/data/extra/web/js/nodelinemapper.js b/src/data/extra/web/js/nodelinemapper.js
index 026a6bae..abfb1334 100644
--- a/src/data/extra/web/js/nodelinemapper.js
+++ b/src/data/extra/web/js/nodelinemapper.js
@@ -201,6 +201,8 @@ class NodeLineMapper {
         let lineNumber = -1;
         if (idx > -1) {
             lineNumber = parseInt(this.nodesWithSourceLine[idx].getAttribute(this.sourceLineAttributeName));
+        } else if (document.documentElement.scrollTop < 30) {
+            lineNumber = 0;
         }
 
         this.adapter.setTopLineNumber(lineNumber);
diff --git a/src/widgets/editors/markdownviewer.cpp b/src/widgets/editors/markdownviewer.cpp
index 2fdb0ff0..b6143abc 100644
--- a/src/widgets/editors/markdownviewer.cpp
+++ b/src/widgets/editors/markdownviewer.cpp
@@ -16,6 +16,7 @@
 #include <core/configmgr.h>
 #include <core/editorconfig.h>
 #include "../widgetsfactory.h"
+#include "../viewwindow.h"
 
 using namespace vnotex;
 
@@ -30,8 +31,18 @@ MarkdownViewer::MarkdownViewer(MarkdownViewerAdapter *p_adapter,
                                const QColor &p_background,
                                qreal p_zoomFactor,
                                QWidget *p_parent)
+    : MarkdownViewer(p_adapter, nullptr, p_background, p_zoomFactor, p_parent)
+{
+}
+
+MarkdownViewer::MarkdownViewer(MarkdownViewerAdapter *p_adapter,
+                               const ViewWindow *p_viewWindow,
+                               const QColor &p_background,
+                               qreal p_zoomFactor,
+                               QWidget *p_parent)
     : WebViewer(p_background, p_zoomFactor, p_parent),
-      m_adapter(p_adapter)
+      m_adapter(p_adapter),
+      m_viewWindow(p_viewWindow)
 {
     m_adapter->setParent(this);
 
@@ -115,7 +126,7 @@ void MarkdownViewer::contextMenuEvent(QContextMenuEvent *p_event)
     }
 #endif
 
-    if (!hasSelection()) {
+    if (!hasSelection() && m_viewWindow && m_viewWindow->getMode() == ViewWindowMode::Read) {
         auto firstAct = actions.isEmpty() ? nullptr : actions[0];
         auto editAct = new QAction(tr("&Edit"), menu.data());
         WidgetUtils::addActionShortcutText(editAct,
diff --git a/src/widgets/editors/markdownviewer.h b/src/widgets/editors/markdownviewer.h
index 259507dd..ed7ca96f 100644
--- a/src/widgets/editors/markdownviewer.h
+++ b/src/widgets/editors/markdownviewer.h
@@ -9,6 +9,7 @@ namespace vnotex
 {
     class MarkdownViewerAdapter;
     class PreviewHelper;
+    class ViewWindow;
 
     class MarkdownViewer : public WebViewer
     {
@@ -20,6 +21,12 @@ namespace vnotex
                        qreal p_zoomFactor,
                        QWidget *p_parent = nullptr);
 
+        MarkdownViewer(MarkdownViewerAdapter *p_adapter,
+                       const ViewWindow *p_viewWindow,
+                       const QColor &p_background,
+                       qreal p_zoomFactor,
+                       QWidget *p_parent = nullptr);
+
         MarkdownViewerAdapter *adapter() const;
 
         void setPreviewHelper(PreviewHelper *p_previewHelper);
@@ -62,6 +69,9 @@ namespace vnotex
         // Managed by QObject.
         MarkdownViewerAdapter *m_adapter = nullptr;
 
+        // Nullable.
+        const ViewWindow *m_viewWindow = nullptr;
+
         // Whether this view has hooked the Copy Image Url action.
         bool m_copyImageUrlActionHooked = false;
 
diff --git a/src/widgets/markdownviewwindow.cpp b/src/widgets/markdownviewwindow.cpp
index a9287163..9564cc27 100644
--- a/src/widgets/markdownviewwindow.cpp
+++ b/src/widgets/markdownviewwindow.cpp
@@ -11,6 +11,7 @@
 #include <QProgressDialog>
 #include <QMenu>
 #include <QActionGroup>
+#include <QTimer>
 
 #include <core/fileopenparameters.h>
 #include <core/editorconfig.h>
@@ -147,14 +148,16 @@ void MarkdownViewWindow::setModeInternal(ViewWindowMode p_mode, bool p_syncBuffe
             if (p_syncBuffer) {
                 syncTextEditorFromBuffer(true);
             }
+
+            m_editor->show();
+
+            setEditViewMode(ConfigMgr::getInst().getEditorConfig().getMarkdownEditorConfig().getEditViewMode());
         }
 
         // Avoid focus glitch.
         m_editor->show();
         m_editor->setFocus();
 
-        setEditViewMode(m_editViewMode);
-
         getMainStatusWidget()->setCurrentWidget(m_textEditorStatusWidget.get());
         break;
     }
@@ -320,7 +323,7 @@ void MarkdownViewWindow::setupToolBar()
         auto act = addAction(toolBar, ViewWindowToolBarHelper::Debug);
         connect(this, &ViewWindow::modeChanged,
                 this, [this, act]() {
-                    act->setEnabled(m_mode != ViewWindowMode::Edit);
+                    act->setEnabled(m_mode == ViewWindowMode::Read || m_editViewMode != MarkdownEditorConfig::EditViewMode::EditOnly);
                 });
     }
 }
@@ -334,8 +337,6 @@ void MarkdownViewWindow::setupTextEditor()
 
     updateConfigRevision();
 
-    m_editViewMode = markdownEditorConfig.getEditViewMode();
-
     m_editor = new MarkdownEditor(markdownEditorConfig,
                                   createMarkdownEditorConfig(editorConfig, markdownEditorConfig),
                                   createMarkdownEditorParameters(editorConfig, markdownEditorConfig),
@@ -432,6 +433,7 @@ void MarkdownViewWindow::setupViewer()
 
     auto adapter = new EditorMarkdownViewerAdapter(nullptr, this);
     m_viewer = new MarkdownViewer(adapter,
+                                  this,
                                   VNoteX::getInst().getThemeMgr().getBaseBackground(),
                                   markdownEditorConfig.getZoomFactorInReadMode(),
                                   this);
@@ -1298,7 +1300,11 @@ void MarkdownViewWindow::setEditViewMode(MarkdownEditorConfig::EditViewMode p_mo
 {
     Q_ASSERT(m_mode == ViewWindowMode::Edit);
 
-    m_editViewMode = p_mode;
+    bool modeChanged = false;
+    if (m_editViewMode != p_mode) {
+        m_editViewMode = p_mode;
+        modeChanged = true;
+    }
 
     switch (p_mode) {
     case MarkdownEditorConfig::EditViewMode::EditOnly:
@@ -1307,10 +1313,12 @@ void MarkdownViewWindow::setEditViewMode(MarkdownEditorConfig::EditViewMode p_mo
             m_viewer->hide();
         }
 
-        disconnect(m_editor->getTextEdit(), &vte::VTextEdit::contentsChanged,
-                   this, &MarkdownViewWindow::syncEditorContentsToPreview);
-        disconnect(m_editor, &MarkdownEditor::topLineChanged,
-                   this, &MarkdownViewWindow::syncEditorPositionToPreview);
+        if (modeChanged) {
+            disconnect(m_editor->getTextEdit(), &vte::VTextEdit::contentsChanged,
+                       m_syncPreviewTimer, QOverload<>::of(&QTimer::start));
+            disconnect(m_editor, &MarkdownEditor::topLineChanged,
+                       this, &MarkdownViewWindow::syncEditorPositionToPreview);
+        }
         break;
     }
 
@@ -1319,17 +1327,25 @@ void MarkdownViewWindow::setEditViewMode(MarkdownEditorConfig::EditViewMode p_mo
         m_viewer->show();
         WidgetUtils::distributeWidgetsOfSplitter(m_splitter);
 
-        if (m_viewerReady) {
+        if (modeChanged) {
+            if (!m_syncPreviewTimer) {
+                m_syncPreviewTimer = new QTimer(this);
+                m_syncPreviewTimer->setSingleShot(true);
+                m_syncPreviewTimer->setInterval(300);
+                connect(m_syncPreviewTimer, &QTimer::timeout,
+                        this, &MarkdownViewWindow::syncEditorContentsToPreview);
+            }
+
             connect(m_editor->getTextEdit(), &vte::VTextEdit::contentsChanged,
-                    this, &MarkdownViewWindow::syncEditorContentsToPreview,
+                    m_syncPreviewTimer, QOverload<>::of(&QTimer::start),
                     Qt::UniqueConnection);
             connect(m_editor, &MarkdownEditor::topLineChanged,
                     this, &MarkdownViewWindow::syncEditorPositionToPreview,
                     Qt::UniqueConnection);
-
-            syncEditorContentsToPreview();
         }
 
+        syncEditorContentsToPreview();
+
         break;
     }
 
@@ -1341,7 +1357,7 @@ void MarkdownViewWindow::setEditViewMode(MarkdownEditorConfig::EditViewMode p_mo
 
 void MarkdownViewWindow::syncEditorContentsToPreview()
 {
-    if (isReadMode() || m_editViewMode == MarkdownEditorConfig::EditViewMode::EditOnly) {
+    if (!m_viewerReady || isReadMode() || m_editViewMode == MarkdownEditorConfig::EditViewMode::EditOnly) {
         return;
     }
 
@@ -1350,7 +1366,7 @@ void MarkdownViewWindow::syncEditorContentsToPreview()
 
 void MarkdownViewWindow::syncEditorPositionToPreview()
 {
-    if (isReadMode() || m_editViewMode == MarkdownEditorConfig::EditViewMode::EditOnly) {
+    if (!m_viewerReady || isReadMode() || m_editViewMode == MarkdownEditorConfig::EditViewMode::EditOnly) {
         return;
     }
 
diff --git a/src/widgets/markdownviewwindow.h b/src/widgets/markdownviewwindow.h
index b832147f..830a522d 100644
--- a/src/widgets/markdownviewwindow.h
+++ b/src/widgets/markdownviewwindow.h
@@ -11,6 +11,7 @@ class QSplitter;
 class QStackedWidget;
 class QWebEngineView;
 class QActionGroup;
+class QTimer;
 
 namespace vte
 {
@@ -224,6 +225,8 @@ namespace vnotex
         QActionGroup *m_viewModeActionGroup = nullptr;
 
         MarkdownEditorConfig::EditViewMode m_editViewMode = MarkdownEditorConfig::EditViewMode::EditOnly;
+
+        QTimer *m_syncPreviewTimer = nullptr;
     };
 }
 
diff --git a/src/widgets/toolbarhelper.cpp b/src/widgets/toolbarhelper.cpp
index be3fa3e9..c84ebcfb 100644
--- a/src/widgets/toolbarhelper.cpp
+++ b/src/widgets/toolbarhelper.cpp
@@ -500,6 +500,12 @@ QToolBar *ToolBarHelper::setupSettingsToolBar(MainWindow *p_win, QToolBar *p_too
                             updater.exec();
                         });
 
+        menu->addAction(MainWindow::tr("Contributors"),
+                        menu,
+                        []() {
+                            WidgetUtils::openUrlByDesktop(QUrl("https://github.com/vnotex/vnote/graphs/contributors"));
+                        });
+
         menu->addAction(MainWindow::tr("About"),
                         menu,
                         [p_win]() {