GDPanelFramework 0.0.1

GD Panel Framework

Introduction

Supports in Godot 4.1+ with .Net module. GD Panel Framework is a Godot 4 UI Management System designed to provide a flexible, panel-based, single-focus point, Gamepad + Keyboard + Keyboard&Mouse friendly UI programming experience.

This framework groups sets of user interactions into a UIPanel, which includes a combination of the following:

1. Controls, such as button, label, and container.
2. Inputs, which is a set of developer-defined input actions binds with this panel.

These user interactions are panel-scoped, which means they only stay active when the panel is active; this simplifies the workflow for maintaining large amounts of discrete Controls and Global Input Actions and allows developers to focus on programming game logic (not collecting and toggling Controls or adding more ifs into a global _Input method).

Installation

WIP: Nuget

Table of Contents

• Simple API Usage
  • Creating a simple panel
  • Creating a panel with Argument
• Framework Documentation
  • Framework Concept
  • The UIPanel
    • Instantiate a Panel
    • Open a panel
    • Close a panel
    • Input Binding / Routing
      • Input Registration
        • Basic Usage
        • Variation: RegisterInputCancel/RemoveInputCancel/ToggleInputCancel
        • Variation: EnableCloseWithCancelKey and DisableCloseWithCancelKey
        • Variation: RegisterInputAxis/RemoveInputAxis/ToggleInputAxis
        • Variation: RegisterInputVector/RemoveInputVector/ToggleInputVector
      • the BuiltinInputNames Class
    • Panel Stack
    • Framework-level Caching
    • Panel Event Methods Overview
    • Configuring the Previous Panel Visual Behavior
  • The UIPanelArg
  • Panel Container Management
  • The Panel Tweener
    • Built-in Tweeners
    • Customized Tweenrs
  • Note when using async/await Styled API
  • Note when using this Framework

Simple API Usage

Creating a simple panel

You can run RunMe_Example00.tscn in Godot Editor.

using Godot;
using GodotTask;

namespace GDPanelFramework.Examples;

/// <summary>
/// The bootstrap script that creates and opens the panel.
/// </summary>
public partial class Example00_Main : Node
{
    /// <summary>
    /// The packed panel.
    /// </summary>
    [Export] private PackedScene _panelPrefab;

    /// <summary>
    /// Executes the main logic after one frame since the game starts. 
    /// This is required by the GDPanelFramework for adding its panel root into the scene tree.
    /// </summary>
    public override void _Ready() =>
        GDTask.NextFrame().ContinueWith(OnReady);

    private void OnReady()
    {
        _panelPrefab
            .CreatePanel<Example00_MyPanel>() // This extension method tells the framework to create or reuse an instance of this panel.
            .OpenPanel( // This method tells the framework to opens the panel.
                onPanelCloseCallback: // This delegate gets called when this panel gets closed when the panel itself calls ClosePanel().
                () => GetTree().Quit() // Terminate the application when this panel gets closed.
            );
    }
}

using GDPanelFramework.Panels;
using Godot;

namespace GDPanelFramework.Examples;

/// <summary>
/// Attach this script to a Control to make it a "UIPanel".
/// </summary>
public partial class Example00_MyPanel : UIPanel
{
    // These three fields are assigned in Godot Editor, through inspector.
    [Export] private Label _text;
    [Export] private Button _updateButton;
    [Export] private Button _closeButton;

    // Stores the click count.
    private int _clickCount = 0;

    /// <summary>
    /// Called by the framework when this instance of panel is created,
    /// an instance can only gets created once.
    /// </summary>
    protected override void _OnPanelInitialize()
    {
        _updateButton.Pressed += OnClick; // Calls OnClick then the _updateButton gets pressed.
        _closeButton.Pressed += ClosePanel; // Close this panel when the _closeButton gets pressed.
    }

    /// <summary>
    /// Registered to the <see cref="_updateButton"/>.
    /// </summary>
    private void OnClick()
    {
        _clickCount++;
        _text.Text = $"Clicked {_clickCount} time(s).";
    }

    /// <summary>
    /// Called by the framework when this instance of panel is opened. 
    /// The framework supports automatic panel caching
    /// so you may reopen a panel after it's closed and cached.
    /// </summary>
    protected override void _OnPanelOpen()
    {
        _text.Text = "Hello World";
        _updateButton.GrabFocus();
    }
}

Creating a panel with Argument

You can run RunMe_Example01.tscn in Godot Editor.

using Godot;
using GodotTask;

namespace GDPanelFramework.Examples;

/// <summary>
/// The bootstrap script that creates and opens the panel.
/// </summary>
public partial class Example01_Main : Node
{
    /// <summary>
    /// The packed panel.
    /// </summary>
    [Export] private PackedScene _panelPrefab;

    /// <summary>
    /// Executes the main logic after one frame since the game starts. 
    /// This is required by the GDPanelFramework for adding its panel root into the scene tree.
    /// </summary>
    public override void _Ready() =>
        GDTask.NextFrame().ContinueWith(OnReady);

    private void OnReady()
    {
        _panelPrefab
            .CreatePanel<Example01_MyPanel>() // This extension method tells the framework to create or reuse an instance of this panel.
            .OpenPanel( // This method tells the framework to opens the panel.
                "Hello World!", // Passes the argument to the panel.
                onPanelCloseCallback: // This delegate gets called when this panel gets closed when the panel itself calls ClosePanel().
                result => // Prints the result and terminate the application when this panel gets closed.
                {
                    GD.Print($"Clicked {result} time(s) before closed.");
                    GetTree().Quit();
                }
            );
    }
}

using GDPanelFramework.Panels;
using Godot;

namespace GDPanelFramework.Examples;

/// <summary>
/// Attach this script to a Control to make it a "UIPanel".
/// </summary>
public partial class Example01_MyPanel : UIPanelArg<string, string>
{
    // These three fields are assigned in Godot Editor, through inspector.
    [Export] private Label _text;
    [Export] private Button _updateButton;
    [Export] private Button _closeButton;

    // Stores the click count.
    private int _clickCount = 0;

    /// <summary>
    /// Called by the framework when this instance of panel is created,
    /// an instance can only gets created once.
    /// </summary>
    protected override void _OnPanelInitialize()
    {
        _updateButton.Pressed += OnClick; // Calls OnClick then the _updateButton gets pressed.
        _closeButton.Pressed += () => ClosePanel(_clickCount.ToString()); // Close this panel when the _closeButton gets pressed.
    }

    /// <summary>
    /// Registered to the <see cref="_updateButton"/>.
    /// </summary>
    private void OnClick()
    {
        _clickCount++;
        _text.Text = $"Clicked {_clickCount} time(s).";
    }

    /// <summary>
    /// Called by the framework when this instance of panel is opened. 
    /// The framework supports automatic panel caching
    /// so you may reopen a panel after it's closed and cached.
    /// </summary>
    protected override void _OnPanelOpen(string openArg)
    {
        _text.Text = openArg;
        _updateButton.GrabFocus();
    }
}

Framework Documentation

Framework Concept

In a typical GUI application such as Games, a panel/page-based control flow is a common practice.

When opening a panel from the main logic, developer may want the panel executes its own panel logic and self closes when finish, then continue the main logic (such as file dialog or warning).

This design transfers the control flow from the main logic to the panel, and the panel returns the control flow back to the main logic when finish simplifies the workflow for programming panels, it handles the requirement for managing ui focuses, and is crucial when designing game pad compatible games.

This framework implementing this practice by the Panel Stack based Control Management, Async/Callback Styled API, and Panel Input Binding design.

The UIPanel

UIPanel is the fundamental component of the framework, it provides Panel Level Input Binding, Child Control Access Management features for simplfying programming workflow, it also supports configurable Panel Tweener for animated opening/closing requirements.

• The Panel Level Input Binding feature allows developers to register/deregister a set of input bindings for this panel, the registered inputs are sandboxed at the panel level so they don't get in the way when panel is inactive.

• The Child Control Access Management feature automatically disables/restores the FocusMode and MouseFilter property for every child control when the panel activates/deactivates, this prevents unwanted UI Navigation and Mouse Interaction to leaked behind the current activated panel.

Instantiate a Panel

Call CreatePanel<TPanel> to instatiate a panel from the supplied PackedScene, instead of the built-in PackedScene.Instantiate, this API also handles necessary initialization and caching.

// In caller class.
[Export] private PackedScene _panelPrefab;

// In caller method.
var panelInstance = 
        _panelPrefab
            .CreatePanel<TypeOfScriptAttachedToThePanel>();

Open a panel

There are three OpenPanel Methods for a UIPanel each of which is designed for a certain programming style.

In an async method, a async/await-styled opening method returns a one-time awaitable that allows the developer to await for a panel close, in PanelArg, awaiting this awaitable will also get the return value from the panel.

// When opening a panel, in async method.
await panelInstance.OpenPanelAsync();
GD.Print("The panel has closed!");

A callback-styled opening method allows the developer to supply a delegate to get notified when the panel has closed, in PanelArg, the return value will also pass to this delegate.

// When opening a panel.
panelInstance
    .OpenPanel(
        onPanelCloseCallback: // This lambda gets called when the panel is closed.
           () => GD.Print("The panel has closed!")
    );

A forget-styled opening method only opens the panel, it is useful when the time of a panel closing is not a concern.

// When opening a panel.
panelInstance.OpenPanel();

Close a panel

Calling ClosePanel() in a panel script will close the opened panel. This method is protected by default, developer may expose this method by wrapping it around by a public one.

Please note that a panel must be opened before you can close it; and closing a panel that's not on top of the panel stack is considered an error and will crash the framework.

// Inside a panel script
protected override void _OnPanelOpen()
{
    // Close a panel one frame after it openes.
    GDTask.NextFrame().ContinueWith(ClosePanel);
}

Input Binding / Routing

All Godot Input Events are intercepted by the root/RootPanelViewport and dispatched directly to the active panel. A set of inputs bound to the panel are automatically switched off or on when the panel deactivates/activates.

Input Registration

Basic Usage

Calling RegisterInput in a panel can bind a delegate to a specific input event, the registered delegates are freed automatically when the panel gets freed.

// In panel
RegisterInput( // Register a callback to the associated inputName
    BuiltinInputNames.UIAccept, // The input name to associate to, this name should Corresponds to the name in InputManager.
    inputEvent => GD.Print(inputEvent.AsText()), // The delegate to associate to.
    InputActionPhase.Pressed // The input state to focus on.
);

In certain cases where unbinding a delegate is required, calling RemoveInput with the corresponding registration.

Note that when working with input deregisteration, to correctly deregisters a lambda expression, it is mandatory to assign the lambda expression to a variable and pass that variable to the APIs.

// Assign this lambda expression to a variable.
Action<InputEvent> myDelegate = inputEvent => GD.Print(inputEvent.AsText());

// Register this callback to the associated inputName.
RegisterInput(BuiltinInputNames.UIAccept, myDelegate);
// Remove this registration.
RemoveInput(BuiltinInputNames.UIAccept, myDelegate);

Alternatively, you may uses the ToggleInput API.

ToggleInput( // This api support change input registration base on the first bool.
    true, // set to false to deregister.
    BuiltinInputNames.UIAccept,
    inputEvent => GD.Print(inputEvent.AsText()) // this lambda expression are cached by the compiler.
);

For achieving certain purposes there are several other variations of input registration APIs.

Variation: RegisterInputCancel/RemoveInputCancel/ToggleInputCancel

Associate a delegate directly to the ui_cancel input event, developer may configure the value in PanelManager.UICancelActionName.

RegisterInputCancel(() => GD.Print("Canceled!"));

Action myDelegate = () => GD.Print("Canceled!");
RegisterInputCancel(myDelegate);
RemoveInputCancel(myDelegate);

ToggleInputCancel(true, () => GD.Print("Canceled!"));

Variation: EnableCloseWithCancelKey and DisableCloseWithCancelKey

UIPanel comes with two extra input binding APIs: EnableCloseWithCancelKey and DisableCloseWithCancelKey, Calling EnableCloseWithCancelKey allows the player to close the current panel with ui_cancel (PanelManager.UICancelActionName), and DisableCloseWithCancelKey revert this behavior.

Variation: RegisterInputAxis/RemoveInputAxis/ToggleInputAxis

Associate a delegate to the composites of two input, similar to what Input.GetAxis does.

RegisterInputAxis(
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    value => GD.Print(value),
    CompositeInputActionState.Update // Start, End
);

Action<float> myDelegate = value => GD.Print(value);
RegisterInputAxis(
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    myDelegate,
    CompositeInputActionState.Update
);
RemoveInputAxis(
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    myDelegate,
    CompositeInputActionState.Update
);

ToggleInputAxis(
    true,
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    value => GD.Print(value),
    CompositeInputActionState.Update
);

Variation: RegisterInputVector/RemoveInputVector/ToggleInputVector

Associate a delegate to the composites of four input, similar to what Input.GetVector does.

RegisterInputVector(
    BuiltinInputNames.UIUp,
    BuiltinInputNames.UIDown,
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    value => GD.Print(value),
    CompositeInputActionState.Update // Start, End
);

Action<Vector2> myDelegate = value => GD.Print(value);
RegisterInputVector(
    BuiltinInputNames.UIUp,
    BuiltinInputNames.UIDown,
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    myDelegate,
    CompositeInputActionState.Update
);
RemoveInputVector(
    BuiltinInputNames.UIUp,
    BuiltinInputNames.UIDown,
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    myDelegate,
    CompositeInputActionState.Update
);

ToggleInputVector(
    true,
    BuiltinInputNames.UIUp,
    BuiltinInputNames.UIDown,
    BuiltinInputNames.UILeft,
    BuiltinInputNames.UIRight,
    value => GD.Print(value),
    CompositeInputActionState.Update
);

the BuiltinInputNames Class

Godot provides a list of builtin ui input event names, developer may access these input names from the BuiltinInputNames class.

Panel Stack

The Panel Stack is designed for maintaining the order of the opened panels, when opening a panel, the framework peeks at the panel stack for the top panel, disable every control under it (their opening statuses are cached), and push this new instance to the stack. When closing the top panel, the framework pops it from the panel stack and reactivates all the control for the panel underneath it, it also set the focus to the last selected item before this panel becomes inactive.

The example below shows the panel stack of the following sequence of operations:

timeline
   No Panel
   Open MainPanel : MainPanel (Active)
   Open SettingPanel : SettingPanel (Active) : MainPanel (Deactivated)
   Open SettingConfirmPanel : SettingConfirmPanel (Active) : SettingPanel  (Deactivated): MainPanel (Deactivated)
   Close SettingConfirmPanel : SettingPanel (Reactivated) : MainPanel (Deactivated)
   Close SettingPanel : MainPanel (Reactivated)
   Close MainPanel

Framework-level Caching

In certain cases where a panel requires frequent opening and closing by design (think about the inventory panel in some games), instantiating a panel everytime and delete it on close can be expensive. To resolve this performance issue, the framework does automatically panel caching that you can configure on a per opening/closing basis.

When creating a panel, by specifying the createPolicy, you may choose to force the framework instantiate a new instance of the panel (CreatePolicy.ForceCreate) or let the framework reuse a cached instance (default) if possible (CreatePolicy.TryReuse), of course, if there is no existing cache, a new instance is created anyway.

// When creating a panel.
var panelInstance = 
        _panelPrefab
            .CreatePanel<TPanel>(
                createPolicy: CreatePolicy.ForceCreate // CreatePolicy.TryReuse
            );

When opening a panel, by specifying the closePolicy, you may choose to instruct the framework to delete this instance (ClosePolicy.Delete) after the transition completes or let the framework to cache this instance (default) (ClosePolicy.Cache), which you can reuse when the calling CreatePanel on the same PackedScene next time.

// When opening a panel.
panelInstance
    .OpenPanel(
        closePolicy: ClosePolicy.Delete // ClosePolicy.Cache
    );

Panel Event Methods Overview

While working with UIPanels, certain methods get called at a certain lifetime of a panel, a brief diagram of the panel can be summarised as follows.

---
title: The Summary for Event Methods throughout the lifetime of UIPanel
---
flowchart TD

id1["_OnPanelInitialize()"]
id2["_OnPanelOpen()"]
id3(["ClosePanel()"])
id4["_OnPanelClose()"]
id5["_OnPanelPredelete()"]
id6["_OnPanelNotification()"]


id0[["Framework Calls"]] -.-> id1
id1 -.->|Framework Calls|id2

subgraph Called Multiple Times before the Panel gets Freed
id2 --> id3
id3 -.->|Framework Calls|id4
id4 -.->|Framework Calls|id2
end
id6 -.->|Framework Calls|id5
id7[["Godot Calls"]] -.-> id6

1. When calling CreatePanel<TPanel>(PackedScene) and causing a new instance of the creation, after the framework has done basic initializing, the _OnPanelInitialize method of that instance gets invoked. This method gets called only once throughout the panel lifetime; that means, if the CreatePanel has reused an instance of the panel, this method is not invoked again.
2. When calling any of the OpenPanel on a non-opened panel instance, after the framework has done preparations for opening this panel, the _OnPanelOpen method gets invoked. For a closed panel that gets cached, _OnPanelOpen will get re-invoked when the panel gets reopened.
3. When calling the ClosePanel, after the framework has done preparations for closing this panel, the _OnPanelClose method gets invoked. For a panel that gets cached, _OnPanelClose will get re-invoked when the panel gets reopened and closed.
4. A UIPanel delegates the _Notification engine call to _OnPanelNotification, and calls _OnPanelPredelete when necessary.

Configuring the Previous Panel Visual Behavior

When opening a new panel, the currently active panel becomes unavailable (such as buttons will no longer be clickable or focusable), you may also control whether the current panel should stay visible or hidden.

Setting the previousPanelVisual to PreviousPanelVisual.Hidden in OpenPanel, will instruct the framework to hide the previous panel using its PanelTweener, otherwise the panel will stays visible (default) (PreviousPanelVisual.Visible).

// When opening a panel.
panelInstance
    .OpenPanel( // Any panel opening method.
        previousPanelVisual: PreviousPanelVisual.Hidden // PreviousPanelVisual.Visible
    );

The UIPanelArg

precautionsIt is a common practice for passing the argument to/receiving return value from a panel, UIPanelArg<TOpenArg, TCloseArg> is here to achieve this requirement.

// MyArgumentPanel.cs
// Defines a panel that accepts an int as the opening argument, and string as the returning value.
public partial class MyArgumentPanel : UIPanelArg<int, string>
{
    protected override void _OnPanelOpen(int openArg) // The opening argument passed from the caller.
    {
        GD.Print($"Opened with argument: {openArg}");
        ClosePanel(openArg.ToString()); // The ClosePanel method requires a return value.
    }
}

Different from the regular UIPanel type, the OpenPanel methods of a UIPanelArg accepts an extra argument and passes it to the _OnPanelOpen(TOpenArg) panel event method and its async/callback-styled overload has its way for obtaining the return value.

// In caller class.
[Export] private PackedScene _panelPrefab;

// In caller method.
var argPanelInstance = _panelPrefab.CreatePanel<MyArgumentPanel>();

// Async/Await-styled open method.
string returnValue = await argPanelInstance.OpenPanelAsync(10); // return value is "10".

// Callback/Delegate-styled open method.
argPanelInstance.OpenPanel(10, onPanelCloseCallback: value => GD.Print(value == "10")) // prints true when the panel closes.

The UIPanelArg supports both passing an argument and returning a value, if one of the features is not needed, you may use the Empty struct to serve as a placeholder.

// The definition for a panel that does't requires opening argument.
public partial class MyArgumentPanel : UIPanelArg<Empty, string>
{
    protected override void _OnPanelOpen(Empty _)
    {
        ClosePanel("Hello World!");
    }
}

// In caller method
argPanelInstance.OpenPanelAsync(Empty.Default);

// The definition for a panel that doesn't requires returning value.
public partial class MyArgumentPanel : UIPanelArg<int, Empty>
{
    protected override void _OnPanelOpen(int openArg)
    {
        GD.Print($"Opened with argument: {openArg}");
        ClosePanel(Empty.Default);
    }
}

Panel Container Management

All panels in are instantiated under root/RootPanelViewport/PanelRoot by default, developers may configure the container for the opening panel through a series of APIs.

Similar to the Panel Stack, Panel Container Stack is design for managing the panel containers, developer may use push a control to the panel container stack using PanelManager.PushPanelContainer, and pop the topmost container by PanelManager.PopPanelContainer. Same as the restrictions of opening and closing panel, developers are only allowed to pop the topmost container before they are allowed to pop the other containers.

To preventing unexpected poping of containers, each PushPanelContainer operation is authorised by a Node, that is, you need to provide a key when pushing a new container, and popping the container with the same key.

// In class
[Export] private Control _myContainer;

// In method

// Every opened panel after this line will get instantiating/reparenting under _myContainer.
PanelManager.PushPanelContainer(this, _myContainer);

// Every opened panel after this line will get instantiating/reparenting under the default panel container.
PanelManager.PopPanelContainer(this);

Please note that, when working with customized panel containers, be careful when spawning panels under a panel/custom container that's getting deleted in the future, while the framework is trying its best to handle deleted panels, it is possible to delete custom panel containers that have active panels lives under, such behavior will possibly crash the framework, developers are recommended to ensure every panel under a custom container has closed before poping/deleting that container.

The Panel Tweener

Developers may customize a panel's visual transition behavior when opening/closing by accessing its PanelTweener property, or modifying the PanelManager.DefaultPanelTweener to set the default tweener for all panels globally.

Built-in Tweeners

There are two preconfigured Tweenrs provided with the framework.

1. NonePanelTweener: This tweener simply hides and shows the panel instantly on open and close, it is also the default value of PanelManager.DefaultPanelTweener, you may access the global instance of this tweener from NonPanelTweener.Instance.
2. FadePanelTweener: This tweener performs fade transition for the panel opening and closing, after instansiating the tweener, you may configure the transition time by accessing its FadeTime property.

Customized Tweenrs

By inheriting the IPanelTweenr interface, developer may customize their own transition effects.

/// <summary>
/// Defines the behavior for panel transitions.
/// </summary>
public interface IPanelTweener
{
    /// <summary>
    /// This sets the default visual appearance for a panel.
    /// </summary>
    /// <param name="panel">The target panel.</param>
    void Init(Control panel);
    
    /// <summary>
    /// This async method manages the behavior when the panel is showing up.
    /// </summary>
    /// <param name="panel">The target panel.</param>
    /// <param name="onFinish">Called by the method when the behavior is considered finished, or not be called at all if the behaviour is interrupted</param>
    void Show(Control panel, Action? onFinish);
    
    /// <summary>
    /// This async method manages the behavior when the panel is hiding out.
    /// </summary>
    /// <param name="panel">The target panel.</param>
    /// <param name="onFinish">Called by the method when the behavior is considered finished, or not be called at all if the behaviour is interrupted</param>
    void Hide(Control panel, Action? onFinish);
}

Note when using async/await Styled API

Most asynchronous methods in the framework are written in callback/delegate style, that is, have a Action onFinish argument in their method signature.

In order to provide an async/await styled programming experience, the AsyncInterop utiliy class is used for convert a callback/delegate styled API into async/await styled one.

The returned AsyncAwaitable can be used with the await keyword, similar to ValueTask, developers may only await for this value once.

public void CallbackStyledMethod(Action onFinish);

public AsyncAwaitable AsyncAwaitStyledMethodAsync()
{
    return AsyncInterop.ToAsync(CallbackStyledMethod);
}

public void CallbackStyledMethodWithReturn(Action<int> onFinish);

public AsyncAwaitable<int> AsyncAwaitStyledMethodWithReturnAsync()
{
    return AsyncInterop.ToAsync<int>(CallbackStyledMethodWithReturn);
}

Note when using this Framework

While there are precautions taken in order to prevent framework crashes, there are still certain

The following panel event methods are execute in under try ... catch bloack, throwing exceptions in the overrides of these methods will not crash the framework.

• _OnPanelInitialize
• _OnPanelOpen
• _OnPanelClose
• _OnPanelPredelete
• _OnPanelNotification
• Registered input events

The following usage WILL crash the framework:

• Creating a panel by specifying a type that's not equal to the type of the Script.
• Openning a panel that's not initialized, which probably means the instance of this panel is not obtained through CreatePanel API.
• Openning a panel that's already opened.
• Closing a panel that's not the last opened panel.
• Providing an invalid CompositeInputActionState enum.
• Authorising a panel container popping with a node which is pushed by a different node.
• Awaiting an AsyncAwaitable that has already awaited.
• Calling GetResult() on an AsyncAwaitable that has not completed yet.