FIX: Error thrown when Cancelling Control Scheme creation in Input actions Editor (ISXB-892) (#1939)

* fixed error thrown when Cancelling Control Scheme creation in Input Actions Editor

Author: bmalrat

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -16,6 +16,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed resource designation for "d_InputControl" icon to address CI failure.
 - Fixed an issue where a composite binding would not be consecutively triggered after disabling actions while there are action modifiers in progress [ISXB-505](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-505).
 - Fixed prefabs and missing default control scheme used by PlayerInput component are now correctly shown in the inspector [ISXB-818](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-818)
+- Fixed error thrown when Cancelling Control Scheme creation in Input Actions Editor.
 
 ## [1.8.2] - 2024-04-29
 

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/Commands/ControlSchemeCommands.cs

@@ -135,9 +135,10 @@ public static Command ResetSelectedControlScheme()
         {
             return (in InputActionsEditorState state) =>
             {
-                var controlSchemeSerializedProperty = state.serializedObject
-                    .FindProperty(nameof(InputActionAsset.m_ControlSchemes))
-                    .GetArrayElementAtIndex(state.selectedControlSchemeIndex);
+                var controlSchemeSerializedProperty = state.selectedControlSchemeIndex == -1 ? null :
+                    state.serializedObject
+                        .FindProperty(nameof(InputActionAsset.m_ControlSchemes))
+                        .GetArrayElementAtIndex(state.selectedControlSchemeIndex);
 
                 if (controlSchemeSerializedProperty == null)
                 {