Fixed an intermittent crash when invoking New Scene

Multiselect item will get cleared, too, and can't be accesed. Ignore
scene change events during cleaning, because those want to access the
multi select item.

CHANGELOG.rst

@@ -27,6 +27,7 @@ Fixed
 * Fixed a crash when importing images with unsupported exif orientation info
 * Fixed threading issue when importing images (causing potential
   hangs/weird behaviour)
+* Fixed an intermittent crash when invoking New Scene
 
 
 

beeref/scene.py

@@ -45,20 +45,22 @@ class BeeGraphicsScene(QtWidgets.QGraphicsScene):
         self.max_z = 0
         self.min_z = 0
         self.Z_STEP = 0.001
-        self.multi_select_item = MultiSelectItem()
-        self.rubberband_item = RubberbandItem()
         self.selectionChanged.connect(self.on_selection_change)
         self.changed.connect(self.on_change)
         self.items_to_add = Queue()
-        self.internal_clipboard = []
         self.edit_item = None
         self.crop_item = None
         self.settings = BeeSettings()
+        self.clear()
+        self._clear_ongoing = False
 
     def clear(self):
+        self._clear_ongoing = True
         super().clear()
         self.internal_clipboard = []
         self.rubberband_item = RubberbandItem()
+        self.multi_select_item = MultiSelectItem()
+        self._clear_ongoing = False
 
     def addItem(self, item):
         logger.debug(f'Adding item {item}')
@@ -452,6 +454,10 @@ class BeeGraphicsScene(QtWidgets.QGraphicsScene):
         return (rect.topLeft() + rect.bottomRight()) / 2
 
     def on_selection_change(self):
+        if self._clear_ongoing:
+            # Ignore events while clearing the scene since the
+            # multiselect item will get cleared, too
+            return
         if self.has_multi_selection():
             self.multi_select_item.fit_selection_area(
                 self.itemsBoundingRect(selection_only=True))
@@ -462,6 +468,10 @@ class BeeGraphicsScene(QtWidgets.QGraphicsScene):
             self.removeItem(self.multi_select_item)
 
     def on_change(self, region):
+        if self._clear_ongoing:
+            # Ignore events while clearing the scene since the
+            # multiselect item will get cleared, too
+            return
         if (self.multi_select_item.scene()
                 and self.multi_select_item.active_mode is None):
             self.multi_select_item.fit_selection_area(