Merge pull request #2745 from kecnry/empty-viewer-select

support deleting all viewers without crashing app

jdaviz/configs/default/plugins/plot_options/plot_options.vue

@@ -39,7 +39,7 @@
       :hint="viewer_multiselect ? 'Select viewers to set options simultaneously' : 'Select the viewer to set options.'"
     />
 
-    <v-row>
+    <v-row v-if="viewer_selected.length > 0">
       <v-expansion-panels accordion>
         <v-expansion-panel>
           <v-expansion-panel-header v-slot="{ open }">
@@ -159,7 +159,7 @@
     </div>
 
     <!-- GENERAL:AXES -->
-    <glue-state-sync-wrapper v-if="axes_visible_sync.in_subscribed_states && config !== 'imviz'" :sync="axes_visible_sync" :multiselect="viewer_multiselect" @unmix-state="unmix_state('axes_visible')">
+    <glue-state-sync-wrapper v-if="axes_visible_sync.in_subscribed_states && viewer_selected.length > 0 && config !== 'imviz'" :sync="axes_visible_sync" :multiselect="viewer_multiselect" @unmix-state="unmix_state('axes_visible')">
       <v-switch
         v-model="axes_visible_value"
         label="Show Axes"

jdaviz/core/template_mixin.py

@@ -2680,6 +2680,8 @@ def _get_selected_item(self, selected):
 
     @property
     def selected_id(self):
+        if self.selected_item is None:
+            return None
         return self.selected_item.get('id', None)
 
     @property
@@ -3582,6 +3584,8 @@ def _state_item(item):
     @cached_property
     def subscribed_icons(self):
         # dictionary items giving information about the entries in subscribed_states
+        if self._viewer_select.selected_item is None:
+            return []
         viewer_icons = self._viewer_select.selected_item.get('icon', [])
         if not isinstance(viewer_icons, list):
             viewer_icons = [viewer_icons]