enable channel multiselection

nexus/nexus.py

@@ -689,6 +689,8 @@ class NexusWindow(*load_ui("NexusWindow.ui")):
         self.root_node = InventoryNode('root')
         self.inv_model = InventoryModel(self.root_node, self)
         self.uiInventoryTree.setModel(self.inv_model)
+        self.uiInventoryTree.setSelectionMode(
+            QtWidgets.QAbstractItemView.ExtendedSelection)
         self.selector = self.uiInventoryTree.selectionModel()
 
         self.inventory = obspyImproved.InventoryIm()
@@ -771,17 +773,16 @@ class NexusWindow(*load_ui("NexusWindow.ui")):
         self.reshape_tree()
 
     def subtract(self):
-        item = self.get_inv_obj_from_selection()
-        self.inventory.delete(item)
+        items = self.get_inv_obj_from_selection()
+        for item in items:
+            i = item.model().get_node(item)._inv_obj
+            self.inventory.delete(i)
         self.inv_model.add_inventory(self.inventory)
         self.reshape_tree()
 
     def get_inv_obj_from_selection(self):
         index_list = self.selector.selectedRows()
-        if len(index_list) != 1:
-            return
-        index = index_list[0]
-        return index.model().get_node(index)._inv_obj
+        return index_list
 
     def calculate_responses(self):
         self.status_message('Calculating responses...')