Preview with the latest GDK does not use a dark titlebar when the system theme is set to "Dark"

The titlebar of latest Minecraft Bedrock Preview no longer supports dark mode in Windows because it now runs on the latest Game Development Kit (as stated in the article for the release of 1.21.120.21 for Bedrock Beta & Preview). Usually, Windows will automatically handle the title bar theming of applications as long as they’re UWP based. This includes using DMW to automatically change the color of the titlebar depending on the system theme, and also applying the Mica material to the titlebar in Windows 11. But, because the game is no longer a UWP app, it has to handle its own titlebar theming. This change causes the application to fallback to the standard Win32 titlebar which is hardcoded white and does not support dark mode. This results in an inconsistency with both the title bar presentation in versions 1.21.120.20 or earlier of Minecraft Preview, and with the title bar presentation of the Minecraft Launcher was just recently updated to fix the same problem (MCL-25102). This also creates an inconsistency with Mac and Linux versions Minecraft Java which both have full support of their respective operating system's title bar theming.ⁱ While Bedrock (specifically the new GDK build) no longer supports proper titlebar theming in Windows 11, other applications that do include, the Minecraft Launcher (versions 3.16.7 and later), Notepad++, Paint.NET, Control Panel, OBS Studio, Kdenlive, and Virtual Box.

Steps to reproduce:

1. Uninstall version 1.21.120.20 or earlier of Minecraft Preview if you have not yet received the GDK version. ⁱⁱ

2. Download and re-install Minecraft Preview from the Microsoft Store or Minecraft Launcher.

3. Open the newly installed GDK version of Minecraft Preview.

4. Observe the titlebar of the Minecraft Preview window.

5. Download and install the Minecraft Launcher from the Microsoft Store.

6. Open version 3.16.7 or above of the Minecraft Minecraft Launcher

7. Observe the titlebar of the fully opened Minecraft Launcher.

Expected Result:

The titlebar of the GDK version of Minecraft Bedrock is painted dark when the system theme is set to “Dark” with additional subtle coloring that is reflective of the current wallpaper and which points to the use of the Mica material. The game also has similar titlebar presentation to that of the Minecraft Launcher for Windows which means that it responds to changes in the system theme.

Observed result:

The titlebar of the GDK version of Minecraft Bedrock is mostly white at all times, even when the system theme is set to “Dark”, with a very subtle hint of color from the hardcoded Mica material that is enabled by default in Windows 11 builds 22557 and above. The game’s titlebar presentation is not in parity with the Minecraft Launcher which has full dark mode support for Windows 11.

Possible Solution (Copied from MCL-25102 ⁱⁱⁱ):

Assuming the Minecraft Launcher is using the standard Windows title bar (which I assume it does based on the fact that the launcher's titlebar has the same light mode transparency materials that were introduced in Windows 11 Build 22557 for the Dev Channel), and according to the official Microsoft documentation on how to Enable a Dark mode title bar for Win32 applications, to support dark mode aware titlebars on applications that do not have Dark Mode support, a developer would need to call the Desktop Window Manager’s DwmSetWindowAttribute function using the window attribute DWMWA_USE_IMMERSIVE_DARK_MODE. Information on how this would be accomplished including helpful code samples are available in the article, “Support Dark and Light themes in Win32 apps”, which can be found at Microsoft’s learn site under “Learn” / “Windows” / “App development”, and then further under “Framework-specific guides” / “Modernize your desktop apps” / “Overview” / ”Apply Windows 11 features”.

Additional Resources:

For additional information on how this could be fixed in the Minecraft Launcher for Windows, here are some developer resources from Microsoft that may relate to this issue:

• Support Dark and Light themes in Win32 apps

• Apply Mica in Win32 desktop apps for Windows 11

• Desktop Window Manager

• DwmSetWindowAttribute function (dwmapi.h)

• DWMWINDOWATTRIBUTE enumeration (dwmapi.h)

• Mica material

ⁱ Despite the fact that Minecraft Java’s titlebar is also white and not theme aware, fixing this issue for Bedrock would not create a parity issue because Java’s handling of its titlebar is also fundamentally incorrect. In fact, Java suffers from this same issue that the Minecraft Launcher suffered from, and now Minecraft Bedrock Preview GDK edition suffers from. In addition, this would not be qualified as a valid parity issue because the differences in the way each version handles its titlebar theming have existed years before Buzzy Beez, so fixing it for Bedrock alone will simply return existing functionality that was lost with the transition to the latest GDK. Its up to the Java team to resolve this problem on their own end.

ⁱⁱ You’ll know you have the updated GDK version of Minecraft Preview if the folder Minecraft Bedrock Preview is found at the path:

C:\Users\%username%\AppData\Roaming\Minecraft Bedrock Preview

You can paste the above path into your Address/Path Bar in File Explorer. If you receive an error that Windows can’t find that folder/path, it means that you don't have the updated GDK version of Minecraft Preview, or you installed Minecraft Preview to a different drive.

Thanks to @SmokeyStack_ for this tip!

ⁱⁱⁱ Since this is basically the same issue that the Minecraft Preview suffered from previously, the solution is mostly the same. So for ease of viewing, I copied portions of MCL-25102 to this bug report, including the “Possible Solution” section that this disclaimer (iii) is referencing.