diff --git a/Orange/widgets/utils/tests/test_colorgradientselection.py b/Orange/widgets/utils/tests/test_colorgradientselection.py
index eee7ddf3cb3..2bc086cfc02 100644
--- a/Orange/widgets/utils/tests/test_colorgradientselection.py
+++ b/Orange/widgets/utils/tests/test_colorgradientselection.py
@@ -1,11 +1,15 @@
+from unittest.mock import Mock
+
 import numpy as np
 
 from AnyQt.QtTest import QSignalSpy
-from AnyQt.QtCore import Qt, QStringListModel
+from AnyQt.QtCore import Qt, QStringListModel, QModelIndex
 
+from Orange.widgets.utils import itemmodels
 from Orange.widgets.utils.colorgradientselection import ColorGradientSelection
 from Orange.widgets.tests.base import GuiTest
 
+
 class TestColorGradientSelection(GuiTest):
     def test_constructor(self):
         w = ColorGradientSelection(thresholds=(0.1, 0.9))
@@ -68,3 +72,40 @@ def test_slider_move(self):
         low, high = changed[-1]
         self.assertLessEqual(low, high)
         self.assertEqual(high, 0.0)
+
+    def test_center(self):
+        w = ColorGradientSelection(center=42)
+        self.assertEqual(w.center(), 42)
+        w.setCenter(40)
+        self.assertEqual(w.center(), 40)
+
+    def test_center_visibility(self):
+        w = ColorGradientSelection(center=0)
+        w.center_box.setVisible = Mock()
+        model = itemmodels.ContinuousPalettesModel()
+        w.setModel(model)
+        for row in range(model.rowCount(QModelIndex())):
+            palette = model.data(model.index(row, 0), Qt.UserRole)
+            if palette:
+                if palette.flags & palette.Diverging:
+                    diverging = row
+                else:
+                    nondiverging = row
+
+        w.setCurrentIndex(diverging)
+        w.center_box.setVisible.assert_called_with(True)
+        w.setCurrentIndex(nondiverging)
+        w.center_box.setVisible.assert_called_with(False)
+        w.setCurrentIndex(diverging)
+        w.center_box.setVisible.assert_called_with(True)
+
+        w = ColorGradientSelection()
+        self.assertIsNone(w.center_box)
+
+    def test_center_changed(self):
+        w = ColorGradientSelection(center=42)
+        changed = QSignalSpy(w.centerChanged)
+        w.center_edit.setText("41")
+        w.center_edit.editingFinished.emit()
+        self.assertEqual(w.center(), 41)
+        self.assertEqual(list(changed), [[41]])
diff --git a/Orange/widgets/visualize/tests/test_owheatmap.py b/Orange/widgets/visualize/tests/test_owheatmap.py
index d0dbf978055..9dad11c8a0d 100644
--- a/Orange/widgets/visualize/tests/test_owheatmap.py
+++ b/Orange/widgets/visualize/tests/test_owheatmap.py
@@ -2,7 +2,7 @@
 # pylint: disable=missing-docstring, protected-access
 import warnings
 import unittest
-from unittest.mock import patch
+from unittest.mock import patch, Mock
 
 import numpy as np
 from sklearn.exceptions import ConvergenceWarning
@@ -245,6 +245,21 @@ def test_palette_centering(self):
                 colors = image_row_colors(image)
                 np.testing.assert_almost_equal(colors, desired)
 
+    def test_centering_threshold_change(self):
+        data = np.arange(2).reshape(-1, 1)
+        table = Table.from_numpy(Domain([ContinuousVariable("y")]), data)
+        self.send_signal(self.widget.Inputs.data, table)
+
+        cmw = self.widget.color_map_widget
+        palette_index = cmw.findData(
+            colorpalettes.ContinuousPalettes["diverging_bwr_40_95_c42"],
+            Qt.UserRole)
+        cmw.setCurrentIndex(palette_index)
+
+        self.widget.update_color_schema = Mock()
+        cmw.centerChanged.emit(42)
+        self.widget.update_color_schema.assert_called()
+
     def test_palette_center(self):
         widget = self.widget
         model = widget.color_map_widget.model()