Fix: StructureDataViewer without Selection tab (#379)

Passing an list without `Selection` tab to configuration_tabs of StructureDataViewer would throw a `ValueError`, because the code would assume that the Selection tab is always present.
It is fixed by set the tab index as `None` and setting the index in try except block.

Author: danielhollas

aiidalab_widgets_base/viewers.py

@@ -212,8 +212,12 @@ def __init__(
         if configuration_tabs is None:
             configuration_tabs = ["Selection", "Appearance", "Cell", "Download"]
 
+        self.selection_tab_idx = None
         if len(configuration_tabs) != 0:
-            self.selection_tab_idx = configuration_tabs.index("Selection")
+            try:
+                self.selection_tab_idx = configuration_tabs.index("Selection")
+            except ValueError:
+                pass
             self.configuration_box = ipw.Tab(
                 layout=ipw.Layout(flex="1 1 auto", width="auto")
             )
@@ -679,7 +683,7 @@ def _observe_selection(self, _=None):
         self._selected_atoms.value = list_to_string_range(self.selection, shift=1)
 
         # if atom is selected from nglview, shift to selection tab
-        if self._selected_atoms.value:
+        if self._selected_atoms.value and self.selection_tab_idx is not None:
             self.configuration_box.selected_index = self.selection_tab_idx
 
     def apply_selection(self, _=None):