Changing Theme at Runtime does not Update Some Properties

[YourRobotOverlord]

Describe the bug

Some properties are not correctly updated when switching themes at runtime, the ones I have noticed are Dialog.DefaultBorderStyle, Dialog.DefaultShadow, MessageBox.DefaultBorderStyle, Menuv2.DefaultBorderStyle, and Button.DefaultShadow.

To Reproduce

Steps to reproduce the behavior:

1. Run the following code:
   Open UICatalog and open 'Help, About'.
   Observe border style, button shadow, and dialog shadow.

2. Change theme to "Green Phosphor"

From Green Phosphor Theme

      "Green Phosphor": {
        "Dialog.DefaultShadow": "None",
        "FrameView.DefaultBorderStyle": "Single",
        "Window.DefaultBorderStyle": "Single",
        "MessageBox.DefaultBorderStyle": "Single",
        "Button.DefaultShadow": "None",
        "Menuv2.DefaultBorderStyle": "Single",

3. Note that the properties have not changed.

Environment

Please run the following commands in your terminal and paste the output:

OS Information

OS: Microsoft Windows 11 Pro 10.0.26200

Terminal Information

Terminal: Windows Terminal 1.23.12811.0

PowerShell Version

Major Minor Patch PreReleaseLabel BuildLabel

---

7 5 4

.NET Information

Output:

dotnet --version
10.0.100

dotnet --info
.NET SDK:
 Version:           10.0.100
 Commit:            b0f34d51fc
 Workload version:  10.0.100-manifests.355811b7
 MSBuild version:   18.0.2+b0f34d51f

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.26200
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.100\

.NET workloads installed:
 [maui-windows]
   Installation Source: VS 18.0.11205.157
   Manifest Version:    10.0.0/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maui\10.0.0\WorkloadManifest.json
   Install Type:              Msi

 [maccatalyst]
   Installation Source: VS 18.0.11205.157
   Manifest Version:    26.0.11017/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maccatalyst\26.0.11017\WorkloadManifest.json
   Install Type:              Msi

 [ios]
   Installation Source: VS 18.0.11205.157
   Manifest Version:    26.0.11017/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.ios\26.0.11017\WorkloadManifest.json
   Install Type:              Msi

 [android]
   Installation Source: VS 18.0.11205.157
   Manifest Version:    36.1.2/10.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.android\36.1.2\WorkloadManifest.json
   Install Type:              Msi

Configured to use workload sets when installing new manifests.
No workload sets are installed. Run "dotnet workload restore" to install a workload set.

Host:
  Version:      10.0.0
  Architecture: x64
  Commit:       b0f34d51fc

.NET SDKs installed:
  8.0.414 [C:\Program Files\dotnet\sdk]
  8.0.416 [C:\Program Files\dotnet\sdk]
  9.0.307 [C:\Program Files\dotnet\sdk]
  10.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 8.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.22 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

Terminal.Gui Version

Version:

v2 - Pre-Alpha

(v2_develop branch, fresh clone)

[YourRobotOverlord]

It actually seems to mostly work in the 'Themes' scenario, and it seems like the main difference is that Themes.cs calls ConfigurationManager.Apply after changing the theme:

        themeOptionSelector.ValueChanged += (sender, args) =>
                                             {
                                                 OptionSelector? optionSelector = sender as OptionSelector;
                                                 if (optionSelector is null)
                                                 {
                                                     return;
                                                 }
                                                 var newTheme = optionSelector!.Labels! [(int)args.Value!] as string;
                                                 // strip off the leading underscore
                                                 ThemeManager.Theme = newTheme!.Substring (1);
                                                 ConfigurationManager.Apply ();
                                             };

whereas UICatalogTop.cs does not:

                _themesSelector.ValueChanged += (_, args) =>
                                                 {
                                                     if (args.Value is null)
                                                     {
                                                         return;
                                                     }
                                                     ThemeManager.Theme = ThemeManager.GetThemeNames () [(int)args.Value];
                                                 };

Note: I say "mostly" works because you still must change views to get the changes to show:

[tig]

Yep! In the UICatalog case, we somehow lost the call to Apply.

The right place for it is actually in UICatalogApp where we enable CM. I have a fix coming in #4338.

Note there are still cases where Views do not subscribe to CM.Applied, and thus realtime updating of INSTANCES is inconsistent.

What does (or should) work reliably, is the updating of CLASSES, so that new instances get the updated settings.

For example LineCanvas does:

    /// <summary>Creates a new instance.</summary>
    public LineCanvas ()
    {
        // TODO: Refactor ConfigurationManager to not use an event handler for this.
        // Instead, have it call a method on any class appropriately attributed
        // to update the cached values. See Issue #2871
        ConfigurationManager.Applied += ConfigurationManager_Applied;
    }

as does MenuBarv2

    private void OnConfigurationManagerApplied (object? sender, ConfigurationManagerEventArgs e)
    {
        BorderStyle = DefaultBorderStyle;
    }

But Button does not (yet).

The current notification mechanism is fragile and won't scale, so I've resisted using it more broadly.