Linear Projection: Setup model_selected before calculating __invalidated

Orange/widgets/visualize/owlinearprojection.py

@@ -358,6 +358,13 @@ def colors_changed(self):
 
     def set_data(self, data):
         super().set_data(data)
+        self._check_options()
+        self._init_vizrank()
+        self.init_projection()
+
+    def use_context(self):
+        self.model_selected.clear()
+        self.model_other.clear()
         if self.data is not None and len(self.selected_vars):
             d, selected = self.data.domain, [v[0] for v in self.selected_vars]
             self.model_selected[:] = [d[attr] for attr in selected]
@@ -368,10 +375,6 @@ def set_data(self, data):
             self.model_selected[:] = self.continuous_variables[:3]
             self.model_other[:] = self.continuous_variables[3:]
 
-        self._check_options()
-        self._init_vizrank()
-        self.init_projection()
-
     def _check_options(self):
         buttons = self.radio_placement.buttons
         for btn in buttons:
@@ -463,13 +466,6 @@ def projection_name():
             ("Jittering", self.graph.jitter_size != 0 and
              "{} %".format(self.graph.jitter_size))))
 
-    def clear(self):
-        if self.model_selected:
-            self.model_selected.clear()
-        if self.model_other:
-            self.model_other.clear()
-        super().clear()
-
     @classmethod
     def migrate_settings(cls, settings_, version):
         if version < 2:

Orange/widgets/visualize/tests/test_owlinearprojection.py

@@ -1,5 +1,6 @@
 # Test methods with long descriptive names can omit docstrings
 # pylint: disable=missing-docstring
+from unittest.mock import Mock
 import numpy as np
 
 from AnyQt.QtCore import QItemSelectionModel
@@ -159,6 +160,28 @@ def test_set_radius_no_data(self):
         self.send_signal(w.Inputs.data, None)
         w.controls.graph.hide_radius.setSliderPosition(3)
 
+    def test_invalidated_model_selected(self):
+        self.widget.setup_plot = Mock()
+        self.send_signal(self.widget.Inputs.data, self.data)
+        self.widget.setup_plot.assert_called_once()
+
+        self.widget.setup_plot.reset_mock()
+        self.widget.model_selected[:] = self.data.domain[2:]
+        self.widget.variables_selection.removed.emit()
+        self.widget.setup_plot.assert_called_once()
+
+        self.widget.setup_plot.reset_mock()
+        self.send_signal(self.widget.Inputs.data, self.data[:, 2:])
+        self.widget.setup_plot.assert_not_called()
+
+        self.widget.model_selected[:] = self.data.domain[3:]
+        self.widget.variables_selection.removed.emit()
+        self.widget.setup_plot.assert_called_once()
+
+        self.widget.setup_plot.reset_mock()
+        self.send_signal(self.widget.Inputs.data, self.data)
+        self.widget.setup_plot.assert_called_once()
+
 
 class LinProjVizRankTests(WidgetTest):
     """