BF: hack to avoid a crash; maybe fixes psychopy#827

- unsure the proper fix
- this works for me (deletes the row without crashing the app)
- no idea what else might happen (memory leak?)

psychopy/app/dialogs.py

@@ -505,6 +505,52 @@ def onRemoveElement(self, event=None):
         self.DeleteRow(row)
         self.Layout()
         self.parent.Fit()
+    def DeleteRow(self, row):
+        """Deletes an entire row, destroying its objects (if any).
+        """
+        # As for the vertically spanned objects in the given row,
+        # we'll need to move them somewhere safe (so that their objects
+        # won't be destroyed as we destroy the row itself) and respan
+        # them later with a reduced row span (decreased by 1 row).
+        # 1. Get a reference of the vertically spanned objects on this row and
+        #    their span, decrementing their row span by 1.
+        _update_span = {}
+        for c in range(0, self.GetCols()):
+            item = self.FindItemAtPosition((row, c))
+            if item:
+                rs, cs = item.GetSpan().Get()
+                if rs > 1:
+                    _update_span[item.GetWindow()] = (rs - 1, cs)
+        # 2. Unspan all objects.
+        objs = self._resetSpan()
+        # 3. Move the _update_span objects to an adjacent row somewhere safe.
+        for obj in _update_span.keys():
+            item = self.FindItem(obj)
+            org_r, org_c = item.GetPos().Get()
+            if org_r == row:
+                item.SetPos((org_r + 1, org_c))
+        # 4. Destroy all objects on this row.
+        for c in range(0, self.GetCols()):
+            item = self.FindItemAtPosition((row, c))
+            if item:
+                obj = item.GetWindow()
+                self.Detach(obj)
+                print obj, dir(obj)
+                del obj  # JRG edited here; memory leaks?
+
+                #obj.Destroy()  # this line crashes python for me
+        # 5. Shift rows up.
+        self.ShiftRowsUp(row + 1)
+        # 6. Respan all objects.
+        objs.update(_update_span)
+        self._setSpan(objs)
+        # 7. Update references to growable rows.
+        grows = self.growableRows.keys()
+        for r in grows:
+            if r >= row:
+                self.RemoveGrowableRow(r)
+                if r > row:
+                    self.AddGrowableRow(r - 1)
     def getListOfDicts(self):
         """Retrieve the current list of dicts from the grid
         """