diff --git a/application/mainwindow.cpp b/application/mainwindow.cpp
index 77e7e89..546ac36 100644
--- a/application/mainwindow.cpp
+++ b/application/mainwindow.cpp
@@ -85,9 +85,12 @@ void MainWindow::openPlugin()
         }
     }
 
-    ui->tabWidget->addTab(plugin->ui(), plugin->pluginIcon(), plugin->pluginName());
-    ui->tabWidget->widget(ui->tabWidget->count() - 1)->setObjectName(plugin->pluginId());
-    ui->tabWidget->setCurrentIndex(ui->tabWidget->count() - 1);
+    if (plugin->ui() != NULL)
+    {
+        ui->tabWidget->addTab(plugin->ui(), plugin->pluginIcon(), plugin->pluginName());
+        ui->tabWidget->widget(ui->tabWidget->count() - 1)->setObjectName(plugin->pluginId());
+        ui->tabWidget->setCurrentIndex(ui->tabWidget->count() - 1);
+    }
 }
 
 void MainWindow::on_actionOpen_database_triggered()
diff --git a/core/autoform.h b/core/autoform.h
index 34d063a..af84ddf 100644
--- a/core/autoform.h
+++ b/core/autoform.h
@@ -38,12 +38,14 @@ public slots:
         if (!m_serviceConnected)
         {
             this->connect(service(), &IService::dbError, [this](QString msg) {
-                QMessageBox::critical(this, "Database error", msg.toStdString().c_str());
+                QMessageBox::critical(this, this->tr("Database error"), msg.toStdString().c_str());
                 m_saved = false;
             });
             this->connect(service(), &IService::permissionDenied, [this](QString permission) {
-                QMessageBox::critical(this, "Permission denied", permission.toStdString().c_str());
-                m_saved = false;
+                if (permission != PERM_DELETE) {
+                    QMessageBox::critical(this, this->tr("Permission denied"), permission.toStdString().c_str());
+                    m_saved = false;
+                }
             });
             this->connect(service(), &IService::dataChanged, [this]() {
                 m_saved = true;
diff --git a/core/gridform.h b/core/gridform.h
index 2e18917..c057c95 100644
--- a/core/gridform.h
+++ b/core/gridform.h
@@ -22,6 +22,7 @@ public:
     IGridForm(parent)
     {
         m_serviceConnected = false;
+        m_permissionDenied = false;
         m_tableModel = NULL;
         m_formHandler = new DefaultFormHandler();
 
@@ -80,12 +81,13 @@ public:
     }
 
 public slots:
-    void fillData() {
+    bool fillData() {
         if (m_tableModel == NULL) {
             Q_ASSERT(false);
-            return;
+            return false;
         }
 
+        m_permissionDenied = false;
         connectService();
 
         m_tableModel->setData(service()->all());
@@ -105,6 +107,8 @@ public slots:
 
         connect(tableView()->horizontalHeader(), SIGNAL(sectionResized(int,int,int)), this, SLOT(widthChanged(int,int,int)));
         hideColumns(hide);
+
+        return !m_permissionDenied;
     }
 
 private:
@@ -140,12 +144,19 @@ private:
             connect(service(), &IService::dbErrorDelete, [this](QString msg) {
                QMessageBox::critical(this, tr("Database error"), tr(msg.toStdString().c_str()));
             });
+            this->connect(service(), &IService::permissionDenied, [this](QString permission) {
+                if (permission == PERM_READ || permission == PERM_DELETE) {
+                    QMessageBox::critical(this, "Permission denied", permission .toStdString().c_str());
+                    m_permissionDenied = true;
+                }
+            });
 
             m_serviceConnected = true;
         }
     }
 
     bool m_serviceConnected;
+    bool m_permissionDenied;
 
     // IGridForm interface
 protected:
@@ -177,6 +188,7 @@ protected:
 
     void handleDeleteRecord() override
     {
+        m_permissionDenied = false;
         connectService();
         if (m_form == NULL || m_tableModel == NULL || tableView()->currentIndex().row() < 0)
         {
@@ -190,8 +202,12 @@ protected:
         {
             QSharedPointer<T> entity = m_tableModel->itemFromIndex(tableView()->currentIndex());
             service()->erase(entity);
-            m_tableModel->removeRowAt(tableView()->currentIndex());
-            emit dataChanged();
+
+            if (!m_permissionDenied)
+            {
+                m_tableModel->removeRowAt(tableView()->currentIndex());
+                emit dataChanged();
+            }
         }
     }
 };
diff --git a/core/igridform.h b/core/igridform.h
index fb70ab6..01a556d 100644
--- a/core/igridform.h
+++ b/core/igridform.h
@@ -32,7 +32,7 @@ signals:
     void dataChanged();
 
 public slots:
-    virtual void fillData() = 0;
+    virtual bool fillData() = 0;
 
 protected:
     virtual void handleNewRecord() = 0;
diff --git a/core/iplugin.h b/core/iplugin.h
index 8b695a5..1ae33bc 100644
--- a/core/iplugin.h
+++ b/core/iplugin.h
@@ -50,13 +50,14 @@ public:
 
     virtual QWidget *ui() {
         IGridForm *form = qobject_cast<IGridForm*>(m_ui);
+        bool filled = true;
 
         if (form != NULL)
         {
-            form->fillData();
+            filled = form->fillData();
         }
 
-        return m_ui;
+        return filled ? m_ui : NULL;
     }
 
     virtual QWidget *settingsUi() {