add single item to matrix parameter by default

python/plugins/processing/gui/matrixmodelerwidget.py

@@ -57,7 +57,10 @@ def __init__(self, parent=None):
         self.btnRemoveRow.clicked.connect(self.removeRows)
         self.btnClear.clicked.connect(self.clearTable)
 
-        self.tblView.setModel(QStandardItemModel())
+        items = [QStandardItem('0')]
+        model = QStandardItemModel()
+        model.appendColumn(items)
+        self.tblView.setModel(model)
 
         self.tblView.horizontalHeader().sectionDoubleClicked.connect(self.changeHeader)