diff --git a/tests/conftest.py b/tests/conftest.py
index bfe24cf..3c09973 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -300,7 +300,9 @@ def __init__(self, selenium, host):
             '    window.__added__.push.apply(window.__added__, cellIds);'
             '}'
         )
-        self.eval_js_function('api.registerCellsAddedHandler', qmxgraph.js.Variable('callback'))
+        self.eval_js_function(
+            'api.registerCellsAddedHandler', qmxgraph.js.Variable('window.callback')
+        )
 
         selenium.execute_script(
             'callback = function(cellId, newLabel, oldLabel) {'
@@ -310,7 +312,9 @@ def __init__(self, selenium, host):
             '    window.__labels__.push({cellId: cellId, newLabel: newLabel, oldLabel: oldLabel});'  # noqa
             '}'
         )
-        self.eval_js_function('api.registerLabelChangedHandler', qmxgraph.js.Variable('callback'))
+        self.eval_js_function(
+            'api.registerLabelChangedHandler', qmxgraph.js.Variable('window.callback')
+        )
 
     def get_container(self):
         """
diff --git a/tests/test_js_graph.py b/tests/test_js_graph.py
index 5c9ce48..54d7f25 100644
--- a/tests/test_js_graph.py
+++ b/tests/test_js_graph.py
@@ -683,7 +683,7 @@ def test_on_cells_removed(graph_cases) -> None:
     graph = graph_cases('2v_1e')
 
     graph.selenium.execute_script('callback = function(cellIds) {window.cellIds = cellIds;}')
-    graph.eval_js_function('api.registerCellsRemovedHandler', js.Variable('callback'))
+    graph.eval_js_function('api.registerCellsRemovedHandler', js.Variable('window.callback'))
 
     cell_ids = [
         graph.get_id(graph.get_vertices()[0]),
@@ -899,7 +899,7 @@ def test_insert_with_tags(graph_cases, cell_type) -> None:
         '   );'
         '}'
     )
-    graph.eval_js_function('api.registerCellsAddedHandler', js.Variable('callback'))
+    graph.eval_js_function('api.registerCellsAddedHandler', js.Variable('window.callback'))
     tags = {'tagTest': '1'}
 
     cell_id = insert_by_parametrized_type(graph, cell_type, tags=tags)
@@ -1194,7 +1194,9 @@ def test_set_double_click_handler(graph_cases) -> None:
         '    window.__dblClick__.push(cellId);'
         '}'
     )
-    graph.eval_js_function('api.registerDoubleClickHandler', qmxgraph.js.Variable('callback'))
+    graph.eval_js_function(
+        'api.registerDoubleClickHandler', qmxgraph.js.Variable('window.callback')
+    )
 
     actions = ActionChains(graph.selenium)
     actions.double_click(graph.get_vertex())
@@ -1220,7 +1222,9 @@ def test_add_selection_change_handler(graph_cases) -> None:
         '    window.__selectionChange__.push(cellIds);'
         '}'
     )
-    graph.eval_js_function('api.registerSelectionChangedHandler', qmxgraph.js.Variable('callback'))
+    graph.eval_js_function(
+        'api.registerSelectionChangedHandler', qmxgraph.js.Variable('window.callback')
+    )
 
     # Select all cells.
     actions = ActionChains(graph.selenium)
@@ -1271,7 +1275,7 @@ def test_set_popup_menu_handler(graph_cases) -> None:
         '    window.__popupMenu__.push([cellId, x, y]);'
         '}'
     )
-    graph.eval_js_function('api.registerPopupMenuHandler', qmxgraph.js.Variable('callback'))
+    graph.eval_js_function('api.registerPopupMenuHandler', qmxgraph.js.Variable('window.callback'))
 
     vertex_label_el = graph.get_label_element(graph.get_vertex())
     actions = ActionChains(graph.selenium)