diff --git a/demo_r2/mainwindow.cpp b/demo_r2/mainwindow.cpp
index 23c4d35..5ad3ac4 100644
--- a/demo_r2/mainwindow.cpp
+++ b/demo_r2/mainwindow.cpp
@@ -107,7 +107,6 @@ void MainWindow::slotPagesSet(int pagesCount)
 
 void MainWindow::slotPageChanged(int page)
 {
-//    ui->sbPageNavigator->setValue(page);
     m_pageNavigator->setValue(page);
 }
 
@@ -118,8 +117,10 @@ void MainWindow::slotPageNavigatorChanged(int page)
 
 void MainWindow::on_treeWidget_itemClicked(QTreeWidgetItem *item, int )
 {
-    m_report.loadFromFile(item->data(0,Qt::UserRole).toString());
-    m_preview->refreshPages();
+    if (!m_report.isBusy()){
+        m_report.loadFromFile(item->data(0,Qt::UserRole).toString());
+        m_preview->refreshPages();
+    }
 }
 
 void MainWindow::initPercentCombobox()
diff --git a/include/lrreportengine.h b/include/lrreportengine.h
index 814d831..8164036 100644
--- a/include/lrreportengine.h
+++ b/include/lrreportengine.h
@@ -98,6 +98,7 @@ public:
     PreviewReportWidget *createPreviewWidget(QWidget *parent = 0);
     void setPreviewWindowTitle(const QString& title);
     void setPreviewWindowIcon(const QIcon& icon);
+    bool isBusy();
 signals:
     void renderStarted();
     void renderFinished();
diff --git a/limereport/lrreportengine.cpp b/limereport/lrreportengine.cpp
index 7ff4095..a7eaa36 100644
--- a/limereport/lrreportengine.cpp
+++ b/limereport/lrreportengine.cpp
@@ -58,7 +58,7 @@ ReportEnginePrivate::ReportEnginePrivate(QObject *parent) :
     QObject(parent), m_fileName(""), m_settings(0), m_ownedSettings(false),
     m_printer(new QPrinter(QPrinter::HighResolution)), m_printerSelected(false),
     m_showProgressDialog(true), m_reportName(""), m_activePreview(0),
-    m_previewWindowIcon(":/report/images/logo32"), m_previewWindowTitle(tr("Preview"))
+    m_previewWindowIcon(":/report/images/logo32"), m_previewWindowTitle(tr("Preview")), m_reportRendering(false)
 {
     m_datasources= new DataSourceManager(this);
     m_scriptEngineContext = new ScriptEngineContext(this);
@@ -457,6 +457,7 @@ void ReportEnginePrivate::cancelRender()
 {
     if (m_reportRender)
         m_reportRender->cancelRender();
+    m_reportRendering = false;
 }
 
 PageDesignIntf* ReportEngine::createPreviewScene(QObject* parent){
@@ -634,6 +635,11 @@ void ReportEnginePrivate::setSuppressFieldAndVarError(bool suppressFieldAndVarEr
     m_reportSettings.setSuppressAbsentFieldsAndVarsWarnings(suppressFieldAndVarError);
 }
 
+bool ReportEnginePrivate::isBusy()
+{
+    return m_reportRendering;
+}
+
 QString ReportEnginePrivate::previewWindowTitle() const
 {
     return m_previewWindowTitle;
@@ -656,6 +662,7 @@ void ReportEnginePrivate::setPreviewWindowIcon(const QIcon &previewWindowIcon)
 
 ReportPages ReportEnginePrivate::renderToPages()
 {
+    if (m_reportRendering) return ReportPages();
     m_reportRender = ReportRender::Ptr(new ReportRender);
     dataManager()->clearErrors();
     dataManager()->connectAllDatabases();
@@ -664,6 +671,7 @@ ReportPages ReportEnginePrivate::renderToPages()
             this, SIGNAL(renderPageFinished(int)));
     if (m_pages.count()){
         ReportPages result;
+        m_reportRendering = true;
         emit renderStarted();
         m_reportRender->setDatasources(dataManager());
         m_reportRender->setScriptContext(scriptContext());
@@ -676,6 +684,7 @@ ReportPages ReportEnginePrivate::renderToPages()
         m_reportRender->secondRenderPass(result);
         emit renderFinished();
         m_reportRender.clear();
+        m_reportRendering = false;
         return result;
     } else {
         return ReportPages();
@@ -763,6 +772,12 @@ void ReportEngine::setPreviewWindowIcon(const QIcon &icon)
     d->setPreviewWindowIcon(icon);
 }
 
+bool ReportEngine::isBusy()
+{
+    Q_D(ReportEngine);
+    return d->isBusy();
+}
+
 void ReportEngine::setShowProgressDialog(bool value)
 {
     Q_D(ReportEngine);
diff --git a/limereport/lrreportengine.h b/limereport/lrreportengine.h
index 814d831..8164036 100644
--- a/limereport/lrreportengine.h
+++ b/limereport/lrreportengine.h
@@ -98,6 +98,7 @@ public:
     PreviewReportWidget *createPreviewWidget(QWidget *parent = 0);
     void setPreviewWindowTitle(const QString& title);
     void setPreviewWindowIcon(const QIcon& icon);
+    bool isBusy();
 signals:
     void renderStarted();
     void renderFinished();
diff --git a/limereport/lrreportengine_p.h b/limereport/lrreportengine_p.h
index 614bc88..2a6e230 100644
--- a/limereport/lrreportengine_p.h
+++ b/limereport/lrreportengine_p.h
@@ -121,7 +121,7 @@ public:
 
     bool suppressFieldAndVarError() const;
     void setSuppressFieldAndVarError(bool suppressFieldAndVarError);
-
+    bool isBusy();
 signals:
     void    pagesLoadFinished();
     void    datasourceCollectionLoadFinished(const QString& collectionName);
@@ -170,6 +170,7 @@ private:
     QString m_previewWindowTitle;
     QPointer<ReportDesignWindow> m_designerWindow;
     ReportSettings m_reportSettings;
+    bool m_reportRendering;
 };
 
 }