FIX: Allow Copy/Paste between windows (ISX-1823).

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -92,6 +92,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed InputManager.asset file growing in size on each Reset call.
 - Fixed Opening InputDebugger throws 'Action map must have state at this point' error.
 - Fixed Cut/Paste behaviour to match Editor - Cut items will now be cleared from clipboard after pasting.
+- Fixed Pasting items between Input Action Editor windows having no effect until an item in the Action Map/Action lists was selected.
 - Improved window layout to avoid elements being hidden (both the Input Actions in Project Settings, and standalone Input Actions Editor windows).
 - Fixed InputAction asset appearing dirty after rename [ISXB-749](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-749).
 - Fixed Error logged when InputActionsEditor window opened without a valid asset.

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs

@@ -285,6 +285,12 @@ private void DirtyInputActionsEditorWindow(InputActionsEditorState newState)
             UpdateWindowTitle();
         }
 
+        private void OnFocus()
+        {
+            // Apply focus here so that Paste works when users tab into the window (handled in InputActionsEditorView)
+            rootVisualElement.Focus();
+        }
+
         private void OnLostFocus()
         {
             // Auto-save triggers on focus-lost instead of on every change

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/Views/ActionMapsView.cs

@@ -169,6 +169,7 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
 
             if (allowUICommandExecution)
             {
+                // NB: Paste is handled in InputActionsEditorView.
                 switch (evt.commandName)
                 {
                     case CmdEvents.Rename:
@@ -187,11 +188,6 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
                     case CmdEvents.Cut:
                         CutItems();
                         break;
-                    case CmdEvents.Paste:
-                        var isActionCopied = CopyPasteHelper.GetCopiedClipboardType() == typeof(InputAction);
-                        if (CopyPasteHelper.HasPastableClipboardData(typeof(InputActionMap)))
-                            PasteItems(isActionCopied);
-                        break;
                     default:
                         return; // Skip StopPropagation if we didn't execute anything
                 }
@@ -205,6 +201,7 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
         private void OnValidateCommand(ValidateCommandEvent evt)
         {
             // Mark commands as supported for Execute by stopping propagation of the event
+            // Paste is handled in InputActionsEditorView.
             switch (evt.commandName)
             {
                 case CmdEvents.Rename:
@@ -213,7 +210,6 @@ private void OnValidateCommand(ValidateCommandEvent evt)
                 case CmdEvents.Duplicate:
                 case CmdEvents.Copy:
                 case CmdEvents.Cut:
-                case CmdEvents.Paste:
                     evt.StopPropagation();
                     break;
             }

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/Views/ActionsTreeView.cs

@@ -390,6 +390,7 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
 
             if (allowUICommandExecution)
             {
+                // NB: Paste is handled in InputActionsEditorView.
                 var data = (ActionOrBindingData)m_ActionsTreeView.selectedItem;
                 switch (evt.commandName)
                 {
@@ -412,11 +413,6 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
                     case CmdEvents.Cut:
                         CutItems();
                         break;
-                    case CmdEvents.Paste:
-                        var hasPastableData = CopyPasteHelper.HasPastableClipboardData(data.isAction ? typeof(InputAction) : typeof(InputBinding));
-                        if (hasPastableData)
-                            PasteItems();
-                        break;
                     default:
                         return; // Skip StopPropagation if we didn't execute anything
                 }
@@ -430,6 +426,7 @@ private void OnExecuteCommand(ExecuteCommandEvent evt)
         private void OnValidateCommand(ValidateCommandEvent evt)
         {
             // Mark commands as supported for Execute by stopping propagation of the event
+            // Paste is handled in InputActionsEditorView.
             switch (evt.commandName)
             {
                 case CmdEvents.Rename:
@@ -438,7 +435,6 @@ private void OnValidateCommand(ValidateCommandEvent evt)
                 case CmdEvents.Duplicate:
                 case CmdEvents.Copy:
                 case CmdEvents.Cut:
-                case CmdEvents.Paste:
                     evt.StopPropagation();
                     break;
             }

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/Views/CopyPasteHelper.cs

@@ -211,9 +211,13 @@ private static void PasteActionsFromClipboard(InputActionsEditorState state, boo
                 : Selectors.GetSelectedActionMap(state)?.wrappedProperty;
             var actionArray = actionMap?.FindPropertyRelative(nameof(InputActionMap.m_Actions));
             if (actionArray == null) return;
+
             var index = state.selectedActionIndex;
-            if (addLast)
+            if (addLast || index >= actionArray.arraySize)
                 index = actionArray.arraySize - 1;
+            if (index < 0)
+                index = 0;
+
             PasteData(EditorHelpers.GetSystemCopyBufferContents(), new[] {index}, actionArray);
         }
 
@@ -384,7 +388,7 @@ private static bool IsPartOfComposite(string json)
         private static SerializedProperty AddElement(SerializedProperty arrayProperty, string name, int index = -1)
         {
             var uniqueName = InputActionSerializationHelpers.FindUniqueName(arrayProperty, name);
-            if (index < 0)
+            if (index < 0 || index > arrayProperty.arraySize)
                 index = arrayProperty.arraySize;
 
             arrayProperty.InsertArrayElementAtIndex(index);

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/Views/InputActionsEditorView.cs

@@ -1,4 +1,5 @@
 #if UNITY_EDITOR && UNITY_INPUT_SYSTEM_PROJECT_WIDE_ACTIONS
+using CmdEvents = UnityEngine.InputSystem.Editor.InputActionsEditorConstants.CommandEvents;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -22,6 +23,9 @@ internal class InputActionsEditorView : ViewBase<InputActionsEditorView.ViewStat
         private readonly ToolbarMenu m_DevicesToolbar;
         private readonly ToolbarButton m_SaveButton;
 
+        private readonly ActionMapsView m_ActionMapsView;
+        private readonly ActionsTreeView m_ActionsTreeView;
+
         private readonly Action m_SaveAction;
 
         public InputActionsEditorView(VisualElement root, StateContainer stateContainer, bool isProjectSettings,
@@ -36,9 +40,10 @@ public InputActionsEditorView(VisualElement root, StateContainer stateContainer,
                 InputActionsEditorConstants.MainEditorViewNameUxml);
 
             mainEditorAsset.CloneTree(root);
-            var actionsTreeView = new ActionsTreeView(root, stateContainer);
-            CreateChildView(new ActionMapsView(root, stateContainer));
-            CreateChildView(actionsTreeView);
+            m_ActionMapsView = new ActionMapsView(root, stateContainer);
+            m_ActionsTreeView = new ActionsTreeView(root, stateContainer);
+            CreateChildView(m_ActionMapsView);
+            CreateChildView(m_ActionsTreeView);
             CreateChildView(new PropertiesView(root, stateContainer));
 
             m_ControlSchemesToolbar = root.Q<ToolbarMenu>("control-schemes-toolbar-menu");
@@ -103,6 +108,10 @@ public InputActionsEditorView(VisualElement root, StateContainer stateContainer,
                     selectedDeviceIndex = state.selectedDeviceRequirementIndex
                 });
 
+            root.RegisterCallback<ValidateCommandEvent>(OnValidateCommand);
+            root.RegisterCallback<ExecuteCommandEvent>(OnExecuteCommand);
+            root.focusable = true; // Required for CommandEvents to work
+
             s_OnPasteCutElements.Add(this);
         }
 
@@ -240,6 +249,41 @@ public class ViewState
             public int selectedDeviceIndex;
         }
 
+        void OnExecuteCommand(ExecuteCommandEvent evt)
+        {
+            if (allowUICommandExecution)
+            {
+                if (evt.commandName != CmdEvents.Paste)
+                    return;
+
+                var copiedType = CopyPasteHelper.GetCopiedClipboardType();
+
+                if (copiedType == typeof(InputActionMap))
+                {
+                    evt.StopPropagation();
+                    m_ActionMapsView.PasteItems(false);
+                    allowUICommandExecution = false;
+                }
+                else if (copiedType == typeof(InputAction) || copiedType == typeof(InputBinding))
+                {
+                    evt.StopPropagation();
+                    m_ActionsTreeView.PasteItems();
+                    allowUICommandExecution = false;
+                }
+            }
+        }
+
+        void OnValidateCommand(ValidateCommandEvent evt)
+        {
+            // Mark commands as supported for Execute by stopping propagation of the event
+            switch (evt.commandName)
+            {
+                case CmdEvents.Paste:
+                    evt.StopPropagation();
+                    break;
+            }
+        }
+
         internal static List<IPasteListener> s_OnPasteCutElements = new();
 
         public override void DestroyView()