gui: Fix an type error in CallFrontListView

... when the displayed model is empty.

Author: ales-erjavec

Orange/widgets/data/oweditdomain.py

@@ -394,7 +394,8 @@ def __init__(self):
 
         self.domain_model = itemmodels.VariableListModel()
         self.domain_view = QListView(
-            selectionMode=QListView.SingleSelection
+            selectionMode=QListView.SingleSelection,
+            uniformItemSizes=True
         )
         self.domain_view.setModel(self.domain_model)
         self.domain_view.selectionModel().selectionChanged.connect(

Orange/widgets/gui.py

@@ -1090,6 +1090,7 @@ def listView(widget, master, value=None, model=None, box=None, callback=None,
                        CallFrontListView(view),
                        CallBackListView(model, view, master, value))
     misc.setdefault('addSpace', True)
+    misc.setdefault('uniformItemSizes', True)
     miscellanea(view, bg, widget, **misc)
     return view
 
@@ -2500,6 +2501,7 @@ def action(self, values):
 
         selection = QItemSelection()
         for value in values:
+            index = None
             if not isinstance(value, int):
                 if isinstance(value, Variable):
                     search_role = TableVariable
@@ -2508,9 +2510,12 @@ def action(self, values):
                     value = str(value)
                 for i in range(model.rowCount()):
                     if model.data(model.index(i), search_role) == value:
-                        value = i
+                        index = i
                         break
-            selection.select(model.index(value), model.index(value))
+            else:
+                index = value
+            if index is not None:
+                selection.select(model.index(index), model.index(index))
         sel_model.select(selection, sel_model.ClearAndSelect)
 
 

Orange/widgets/utils/listfilter.py

@@ -53,6 +53,7 @@ def __init__(self, parent=None, acceptedType=Orange.data.Variable):
         self.setDragDropMode(self.DragDrop)
         self.setDefaultDropAction(Qt.MoveAction)
         self.setDragDropOverwriteMode(False)
+        self.setUniformItemSizes(True)
         self.viewport().setAcceptDrops(True)
 
         #: type | Tuple[type]