enh: do not keep dataset references in QuickView, only remember IDs

CHANGELOG

@@ -1,6 +1,7 @@
 2.21.5
  - fix: disable table graphs widget when an image-type table is shown
  - fix: accessing table data from DCOR
+ - enh: do not keep dataset references in QuickView, only remember IDs
  - setup: bump dclab to 0.62.13
 2.21.4
  - fix: incorrect path list check when loading broken dataset

shapeout2/gui/quick_view/qv_main.py

@@ -30,8 +30,8 @@ class QuickView(QtWidgets.QWidget):
     polygon_filter_about_to_be_deleted = QtCore.pyqtSignal(int)
 
     def __init__(self, *args, **kwargs):
-        self._hover_ds = None
-        self._hover_event = None
+        self._hover_ds_id = None
+        self._hover_event_idx = None
         super(QuickView, self).__init__(*args, **kwargs)
         ref = importlib.resources.files(
             "shapeout2.gui.quick_view") / "qv_main.ui"
@@ -292,8 +292,8 @@ def _check_file_open(self, rtdc_ds):
         return isopen
 
     def _set_initial_ui(self):
-        self._hover_ds = None
-        self._hover_event = None
+        self._hover_ds_id = None
+        self._hover_event_idx = None
         # Initially, only show the info about how QuickView works
         self.widget_tool.setEnabled(False)
         self.widget_scatter.hide()
@@ -316,8 +316,8 @@ def rtdc_ds(self):
     @rtdc_ds.setter
     def rtdc_ds(self, rtdc_ds):
         if self._rtdc_ds is not rtdc_ds:
-            self._hover_ds = None
-            self._hover_event = None
+            self._hover_ds_id = None
+            self._hover_event_idx = None
 
         self._rtdc_ds = rtdc_ds
 
@@ -574,10 +574,11 @@ def on_event_scatter_hover(self, pos):
             event = np.where(plotted)[0][point.index()]
 
             # Only plot if we have not plotted this event before
-            if self._hover_ds is not ds or self._hover_event != event:
+            if (self._hover_ds_id != id(ds)
+                    or self._hover_event_idx != event):
                 # remember where we were
-                self._hover_ds = ds
-                self._hover_event = event
+                self._hover_ds_id = id(ds)
+                self._hover_event_idx = event
                 view = "view_poly"
                 for key in self.img_info.keys():
                     self.img_info[key][view].hide()