Source trigger patch file drop (#1236)

* Add Signal if File dropped

* Check if Index is valid

Send Signal and return if Index is invalid and File was dropped

* Connect Dropsignal to fileopen

src/ExtendedTableWidget.cpp

@@ -543,6 +543,14 @@ void ExtendedTableWidget::dragMoveEvent(QDragMoveEvent* event)
 void ExtendedTableWidget::dropEvent(QDropEvent* event)
 {
     QModelIndex index = indexAt(event->pos());
+    
+    if (!index.isValid())
+    {
+        if (event->mimeData()->hasUrls() && event->mimeData()->urls().first().isLocalFile())
+            emit openFileFromDropEvent(event->mimeData()->urls().first().toLocalFile());
+        return;
+    }
+    
     model()->dropMimeData(event->mimeData(), Qt::CopyAction, index.row(), index.column(), QModelIndex());
     event->acceptProposedAction();
 }