diff --git a/src/Model/HydraulicStructures/HydraulicStructures.py b/src/Model/HydraulicStructures/HydraulicStructures.py
index 78543a61..5d9a7472 100644
--- a/src/Model/HydraulicStructures/HydraulicStructures.py
+++ b/src/Model/HydraulicStructures/HydraulicStructures.py
@@ -118,8 +118,8 @@ class HydraulicStructure(SQLSubModel):
             )
 
             hs.enabled = enabled
-            hs.input_kp = input_kp
-            hs.output_kp = output_kp
+            hs.input_kp = input_kp if input_kp != -1 else None
+            hs.output_kp = output_kp if output_kp != -1 else None
 
             hs.input_reach, hs.output_reach = reduce(
                 lambda acc, n: (
diff --git a/src/View/HydraulicStructures/Table.py b/src/View/HydraulicStructures/Table.py
index 58e08684..210cf1e8 100644
--- a/src/View/HydraulicStructures/Table.py
+++ b/src/View/HydraulicStructures/Table.py
@@ -80,7 +80,7 @@ class ComboBoxDelegate(QItemDelegate):
             val
         )
 
-        self.editor.setCurrentText(index.data(Qt.DisplayRole))
+        self.editor.setCurrentText(str(index.data(Qt.DisplayRole)))
         return self.editor
 
     def setEditorData(self, editor, index):