diff --git a/execution.py b/execution.py
index dc2b67554..5bf62d678 100644
--- a/execution.py
+++ b/execution.py
@@ -40,17 +40,14 @@ def get_input_data(inputs, class_def, unique_id, outputs={}, prompt={}, extra_da
                 input_data_all[x] = [unique_id]
     return input_data_all
 
-def get_output_data(obj, input_data_all):
-    
+def map_node_over_list(obj, input_data_all, func, allow_interrupt=False):
     # check if node wants the lists
     intput_is_list = False
     if hasattr(obj, "INPUT_IS_LIST"):
         intput_is_list = obj.INPUT_IS_LIST
 
     max_len_input = max([len(x) for x in input_data_all.values()])
-    results = []
-    uis = []
-
+     
     # get a slice of inputs, repeat last input when list isn't long enough
     def slice_dict(d, i):
         d_new = dict()
@@ -58,22 +55,32 @@ def get_output_data(obj, input_data_all):
             d_new[k] = v[i if len(v) > i else -1]
         return d_new
     
-    def append_return(input):
-        nodes.before_node_execution()
-        node_result = getattr(obj, obj.FUNCTION)(**input)
-        if isinstance(node_result, dict):
-            if 'ui' in node_result:
-                uis.append(node_result['ui'])
-            if 'result' in node_result:
-                results.append(node_result['result'])
-        else:
-            results.append(node_result)
-    
+    results = []
     if intput_is_list:
-        append_return(**input_data_all)
+        if allow_interrupt:
+            nodes.before_node_execution()
+        results.append(getattr(obj, func)(**input_data_all))
     else: 
         for i in range(max_len_input):
-            append_return(slice_dict(input_data_all, i))
+            if allow_interrupt:
+                nodes.before_node_execution()
+            results.append(getattr(obj, func)(**slice_dict(input_data_all, i)))
+    return results
+
+def get_output_data(obj, input_data_all):
+    
+    results = []
+    uis = []
+    return_values = map_node_over_list(obj, input_data_all, obj.FUNCTION, allow_interrupt=True)
+
+    for r in return_values:
+        if isinstance(r, dict):
+            if 'ui' in r:
+                uis.append(r['ui'])
+            if 'result' in r:
+                results.append(r['result'])
+        else:
+            results.append(r)
     
     output = []
     if len(results) > 0:
@@ -157,7 +164,8 @@ def recursive_output_delete_if_changed(prompt, old_prompt, outputs, current_item
             input_data_all = get_input_data(inputs, class_def, unique_id, outputs)
             if input_data_all is not None:
                 try:
-                    is_changed = class_def.IS_CHANGED(**input_data_all)
+                    #is_changed = class_def.IS_CHANGED(**input_data_all)
+                    is_changed = map_node_over_list(class_def, input_data_all, "IS_CHANGED")
                     prompt[unique_id]['is_changed'] = is_changed
                 except:
                     to_delete = True
@@ -312,9 +320,11 @@ def validate_inputs(prompt, item):
 
             if hasattr(obj_class, "VALIDATE_INPUTS"):
                 input_data_all = get_input_data(inputs, obj_class, unique_id)
-                ret = obj_class.VALIDATE_INPUTS(**input_data_all)
-                if ret != True:
-                    return (False, "{}, {}".format(class_type, ret))
+                #ret = obj_class.VALIDATE_INPUTS(**input_data_all)
+                ret = map_node_over_list(obj_class, input_data_all, "VALIDATE_INPUTS")
+                for r in ret:
+                    if r != True:
+                        return (False, "{}, {}".format(class_type, r))
             else:
                 if isinstance(type_input, list):
                     if val not in type_input: