[windows] Use application icon as default systray icon if available.

mkdocs-website/docs/en/changelog.md

@@ -43,6 +43,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed service name determination by [windom](https://github.com/windom/) in [#3827](https://github.com/wailsapp/wails/pull/3827)
 - mkdocs serve now uses docker by [leaanthony](https://github.com/leaanthony)
 - Consolidated dev config into `config.yml` by [leaanthony](https://github.com/leaanthony)
+- Systray dialog now defaults to the application icon if available (Windows) by [@leaanthony](https://github.com/leaanthony)
 
 ### Fixed
 - Fixed cross-platform cleanup for .syso files during Windows build by [ansxuman](https://github.com/ansxuman) in [#3924](https://github.com/wailsapp/wails/pull/3924)

v3/pkg/application/systemtray_windows.go

@@ -4,12 +4,11 @@ package application
 
 import (
 	"fmt"
+	"github.com/wailsapp/wails/v3/pkg/icons"
 	"syscall"
 	"time"
 	"unsafe"
 
-	"github.com/wailsapp/wails/v3/pkg/icons"
-
 	"github.com/samber/lo"
 
 	"github.com/wailsapp/wails/v3/pkg/events"
@@ -202,15 +201,21 @@ func (s *windowsSystemTray) run() {
 		panic(syscall.GetLastError())
 	}
 
-	if s.parent.icon != nil {
-		s.lightModeIcon = lo.Must(w32.CreateSmallHIconFromImage(s.parent.icon))
+	// Get the application icon if available
+	defaultIcon := w32.LoadIconWithResourceID(w32.GetModuleHandle(""), w32.RT_ICON)
+	if defaultIcon != 0 {
+		s.lightModeIcon = defaultIcon
+		s.darkModeIcon = defaultIcon
 	} else {
 		s.lightModeIcon = lo.Must(w32.CreateSmallHIconFromImage(icons.SystrayLight))
+		s.darkModeIcon = lo.Must(w32.CreateSmallHIconFromImage(icons.SystrayDark))
+	}
+
+	if s.parent.icon != nil {
+		s.lightModeIcon = lo.Must(w32.CreateSmallHIconFromImage(s.parent.icon))
 	}
 	if s.parent.darkModeIcon != nil {
 		s.darkModeIcon = lo.Must(w32.CreateSmallHIconFromImage(s.parent.darkModeIcon))
-	} else {
-		s.darkModeIcon = lo.Must(w32.CreateSmallHIconFromImage(icons.SystrayDark))
 	}
 	s.uid = nid.UID
 

v3/pkg/w32/constants.go

@@ -159,6 +159,30 @@ const (
 	IDI_INFORMATION = IDI_ASTERISK
 )
 
+const (
+	RT_CURSOR       = 1 // win32.MAKEINTRESOURCE(1)
+	RT_BITMAP       = 2
+	RT_ICON         = 3
+	RT_MENU         = 4
+	RT_DIALOG       = 5
+	RT_STRING       = 6
+	RT_FONTDIR      = 7
+	RT_FONT         = 8
+	RT_ACCELERATOR  = 9
+	RT_RCDATA       = 10
+	RT_MESSAGETABLE = 11
+	RT_GROUP_CURSOR = 12
+	RT_GROUP_ICON   = 14
+	RT_VERSION      = 16
+	RT_DLGINCLUDE   = 17
+	RT_PLUGPLAY     = 19
+	RT_VXD          = 20
+	RT_ANICURSOR    = 21
+	RT_ANIICON      = 22
+	RT_HTML         = 23
+	RT_MANIFEST     = 24
+)
+
 // Button style constants
 const (
 	BS_3STATE          = 5