diff --git a/line.py b/line.py
index 7a68b9a7cd..800daa76c1 100644
--- a/line.py
+++ b/line.py
@@ -27,11 +27,11 @@ class Line(ModelSQL, ModelView):
             ('company', '=', Eval('company', -1)),
             ['OR',
                 ('start_date', '=', None),
-                ('start_date', '<=', Eval('date')),
+                ('start_date', '<=', Eval('date', None)),
                 ],
             ['OR',
                 ('end_date', '=', None),
-                ('end_date', '>=', Eval('date')),
+                ('end_date', '>=', Eval('date', None)),
                 ],
             ],
         depends=['company', 'date'],
@@ -44,11 +44,11 @@ class Line(ModelSQL, ModelView):
             ('company', '=', Eval('company', -1)),
             ['OR',
                 ('timesheet_start_date', '=', None),
-                ('timesheet_start_date', '<=', Eval('date')),
+                ('timesheet_start_date', '<=', Eval('date', None)),
                 ],
             ['OR',
                 ('timesheet_end_date', '=', None),
-                ('timesheet_end_date', '>=', Eval('date')),
+                ('timesheet_end_date', '>=', Eval('date', None)),
                 ],
             ],
         depends=['date', 'company'],
@@ -170,11 +170,11 @@ class EnterLinesStart(ModelView):
             ('company', '=', Eval('context', {}).get('company', -1)),
             ['OR',
                 ('start_date', '=', None),
-                ('start_date', '<=', Eval('date')),
+                ('start_date', '<=', Eval('date', None)),
                 ],
             ['OR',
                 ('end_date', '=', None),
-                ('end_date', '>=', Eval('date')),
+                ('end_date', '>=', Eval('date', None)),
                 ],
             ],
         depends=['date'],