[v3]MacTitleBarHiddenInset causes large fullscreen toolbar area on macOS

[OSpoon]

Hi, I’m using Wails v3 on macOS with the following window configuration:

app.Window.NewWithOptions(application.WebviewWindowOptions{
  Title: "Window 1",
  Mac: application.MacWindow{
	  InvisibleTitleBarHeight: 50,
	  Backdrop:                application.MacBackdropTranslucent,
	  TitleBar:                application.MacTitleBarHiddenInset,
  },
  BackgroundColour: application.NewRGB(27, 38, 54),
  URL:              "/",
})

This works well in normal window mode: the traffic light buttons are positioned nicely with the inset style, and the app can use a custom web-based title/header area.
However, when the window enters macOS fullscreen mode, the top native titlebar/toolbar area becomes unexpectedly tall. A large dark/black region appears above the web content, which makes the fullscreen layout look incorrect.

Is this expected behavior when using MacTitleBarHiddenInset / UseToolbar: true on macOS, or is there a recommended configuration/workaround for keeping inset traffic lights in normal mode while avoiding the large top area in fullscreen?

(base) ➜  wails3-vue-ts-template git:(main) ✗ wails3 doctor-ng
   OS                MacOS 26.5.1
   Platform          darwin/arm64
   CPU               Apple M4
   GPU               10 cores, Metal Support: Metal 4
   Memory            24 GB
   Apple Silicon     true
   Package Manager   homebrew
                 
Build Environment
                 
   Wails   v3.0.0-alpha.98
   Go      go1.26.3
   CGO     true
            
Dependencies
            
  ✓ Xcode CLI Tools           2416
  ✓ npm                       10.9.2
  ✓ docker                    29.4.0, build 9d7ad9f (optional)
  ✗ NSIS                      not installed (optional)

✓ System is ready for Wails development!