diff --git a/src/gui/sellerdialog.cpp b/src/gui/sellerdialog.cpp
index 499f755..2b741d7 100644
--- a/src/gui/sellerdialog.cpp
+++ b/src/gui/sellerdialog.cpp
@@ -14,6 +14,8 @@ SellerDialog::SellerDialog(QWidget* parent, Qt::WindowFlags f) : QDialog(parent,
     ui_.tableView->setColumnHidden(0, true); // hide the uuid
     connect(ui_.newButton, &QPushButton::clicked, this, &SellerDialog::on_newButton_clicked);
     connect(ui_.deleteButton, &QPushButton::clicked, this, &SellerDialog::on_deleteButton_clicked);
+    connect(model, &SellerModel::duplicateSellerNo, this,
+            &SellerDialog::on_model_duplicateSellerNo);
 }
 
 void SellerDialog::on_newButton_clicked()
@@ -33,7 +35,7 @@ void SellerDialog::on_deleteButton_clicked()
     if (selModel->hasSelection() == false)
         return;
     auto indexes = selModel->selectedRows();
-    
+
     std::sort(indexes.begin(), indexes.end());
 
     // Deleting the rows, beginning with the last one!
@@ -42,6 +44,13 @@ void SellerDialog::on_deleteButton_clicked()
     }
 }
 
+void SellerDialog::on_model_duplicateSellerNo(const QString& message)
+{
+    QMessageBox(QMessageBox::Icon::Warning, "Fehler", message, QMessageBox::StandardButton::Ok,
+                this)
+        .exec();
+}
+
 void SellerDialog::accept()
 {
     Marketplace* market = dynamic_cast<MainWindow*>(parentWidget())->getMarketplace();
diff --git a/src/gui/sellerdialog.h b/src/gui/sellerdialog.h
index d539f4a..4276630 100644
--- a/src/gui/sellerdialog.h
+++ b/src/gui/sellerdialog.h
@@ -18,6 +18,7 @@ class SellerDialog : public QDialog
   private:
     void on_newButton_clicked();
     void on_deleteButton_clicked();
+    void on_model_duplicateSellerNo(const QString& message);
     virtual void accept() override;
     Ui::SellerDialog ui_;
 };
diff --git a/src/gui/sellermodel.cpp b/src/gui/sellermodel.cpp
index b59f49e..a8808d7 100644
--- a/src/gui/sellermodel.cpp
+++ b/src/gui/sellermodel.cpp
@@ -23,9 +23,9 @@ QVariant SellerModel::data(const QModelIndex& index, int role) const
 
     Seller* seller = marketplace_->getSellers().at(index.row()).get();
 
-/*     if (seller->getState() == Seller::State::DELETE)
-        return QVariant();
- */
+    /*      if (seller->getState() == Seller::State::DELETE)
+            return QVariant();
+     */
     switch (index.column()) {
     case 0:
         return seller->getUuidAsString().c_str();
@@ -93,9 +93,9 @@ bool SellerModel::setData(const QModelIndex& index, const QVariant& value, int r
                              return value.toInt() == seller->getSellerNo();
                          });
         if (iter != marketplace_->getSellers().end()) {
-            /* QMessageBox(QMessageBox::Icon::Warning, "Fehler",
-                        "Die Verkäufernummer muss eindeutig sein.", QMessageBox::StandardButton::Ok)
-                .exec(); */
+            emit duplicateSellerNo(
+                "Die Verkäufernummer muss eindeutig sein.\n(Möglicherweise wird die Nummer von einem "
+                "Eintrag, der zum Löschen vorgemerkt ist, verwendet.)");
             return false;
         }
         seller->setSellerNo(value.toInt());
@@ -133,19 +133,19 @@ bool SellerModel::insertRows(int row, int count, const QModelIndex& parent)
 
 bool SellerModel::removeRows(int row, int count, const QModelIndex& parent)
 {
-    emit beginRemoveRows(parent, row, row + count - 1);
     auto seller = marketplace_->getSellers().at(row).get();
     if (seller->getState() == Seller::State::NEW) {
+        emit beginRemoveRows(parent, row, row + count - 1);
         marketplace_->getSellers().erase(
             std::remove_if(marketplace_->getSellers().begin(), marketplace_->getSellers().end(),
                            [&seller](const std::unique_ptr<Seller>& a) {
                                return a->getUuid() == seller->getUuid();
                            }),
             marketplace_->getSellers().end());
+        emit endRemoveRows();
     } else {
         seller->setState(Seller::State::DELETE);
     }
-    emit endRemoveRows();
 
     return false;
 }
\ No newline at end of file
diff --git a/src/gui/sellermodel.h b/src/gui/sellermodel.h
index 8a7f61e..4d489fc 100644
--- a/src/gui/sellermodel.h
+++ b/src/gui/sellermodel.h
@@ -7,6 +7,8 @@
 
 class SellerModel : public QAbstractTableModel
 {
+  Q_OBJECT
+
   public:
     explicit SellerModel(Marketplace* market, QObject* parent = nullptr);
     virtual int rowCount(const QModelIndex& parent = QModelIndex()) const override;
@@ -18,6 +20,9 @@ class SellerModel : public QAbstractTableModel
     virtual bool insertRows(int row, int count, const QModelIndex& parent = QModelIndex()) override;
     virtual bool removeRows(int row, int count, const QModelIndex& parent = QModelIndex()) override;
 
+  signals:
+    void duplicateSellerNo(const QString& message);
+
   private:
     Marketplace* marketplace_;
 };