diff --git a/src/ui/layout.go b/src/ui/layout.go
new file mode 100644
index 0000000..798178b
--- /dev/null
+++ b/src/ui/layout.go
@@ -0,0 +1,37 @@
+package ui
+
+import (
+	"fyne.io/fyne/v2"
+)
+
+type minWidthLayout struct {
+	width float32
+}
+
+func (l minWidthLayout) MinSize(objects []fyne.CanvasObject) fyne.Size {
+	width := l.width
+	var height float32
+	for _, object := range objects {
+		if !object.Visible() {
+			continue
+		}
+		min := object.MinSize()
+		if min.Width > width {
+			width = min.Width
+		}
+		if min.Height > height {
+			height = min.Height
+		}
+	}
+	return fyne.NewSize(width, height)
+}
+
+func (l minWidthLayout) Layout(objects []fyne.CanvasObject, size fyne.Size) {
+	for _, object := range objects {
+		if !object.Visible() {
+			continue
+		}
+		object.Move(fyne.NewPos(0, 0))
+		object.Resize(size)
+	}
+}
diff --git a/src/ui/mainwindow.go b/src/ui/mainwindow.go
index 49e22fd..6ed0a18 100644
--- a/src/ui/mainwindow.go
+++ b/src/ui/mainwindow.go
@@ -91,35 +91,3 @@ func newMainView(w fyne.Window) (fyne.CanvasObject, func(time.Duration, bool)) {
 
 	return tabs, recordStartup
 }
-
-type minWidthLayout struct {
-	width float32
-}
-
-func (l minWidthLayout) MinSize(objects []fyne.CanvasObject) fyne.Size {
-	width := l.width
-	var height float32
-	for _, object := range objects {
-		if !object.Visible() {
-			continue
-		}
-		min := object.MinSize()
-		if min.Width > width {
-			width = min.Width
-		}
-		if min.Height > height {
-			height = min.Height
-		}
-	}
-	return fyne.NewSize(width, height)
-}
-
-func (l minWidthLayout) Layout(objects []fyne.CanvasObject, size fyne.Size) {
-	for _, object := range objects {
-		if !object.Visible() {
-			continue
-		}
-		object.Move(fyne.NewPos(0, 0))
-		object.Resize(size)
-	}
-}
diff --git a/src/ui/run.go b/src/ui/run.go
index 9684c9d..f087f82 100644
--- a/src/ui/run.go
+++ b/src/ui/run.go
@@ -1,9 +1,6 @@
 package ui
 
 import (
-	"io"
-	"net"
-	"strings"
 	"time"
 
 	"gitea.mixdep.ru/mix/gosentry/assets"
@@ -11,12 +8,9 @@ import (
 
 	"fyne.io/fyne/v2"
 	fyneapp "fyne.io/fyne/v2/app"
-	fynedesktop "fyne.io/fyne/v2/driver/desktop"
 )
 
 const appID = "ru.mixdep.gosentry.desktop"
-const singleInstanceAddress = "127.0.0.1:37653"
-const singleInstanceShowCommand = "show"
 
 // Run is the application entry point. It owns the process lifecycle — single
 // instance arbitration, Fyne app + window construction, tray wiring, and the
@@ -64,88 +58,3 @@ func Run(startInTray bool) {
 func loadAppIcon() fyne.Resource {
 	return assets.Icon()
 }
-
-func configureSystemTray(a fyne.App, w fyne.Window) {
-	desk, ok := a.(fynedesktop.App)
-	if !ok {
-		// Not every Fyne driver exposes desktop tray features. Returning silently
-		// keeps the same binary usable on platforms or sessions without a tray.
-		return
-	}
-
-	// IsQuit marks this as the tray's quit item. Without it Fyne's
-	// addMissingQuitForMenu appends a second, localized Quit (e.g. "Выход" on a
-	// Russian system) because it only recognizes an existing quit by matching the
-	// localized label — which our literal "Quit" does not. Setting IsQuit makes
-	// Fyne reuse this item instead of adding a duplicate, regardless of locale.
-	quit := fyne.NewMenuItem("Quit", func() {
-		a.Quit()
-	})
-	quit.IsQuit = true
-	menu := fyne.NewMenu("GoSentry",
-		fyne.NewMenuItem("Show", func() {
-			w.Show()
-			w.RequestFocus()
-		}),
-		fyne.NewMenuItemSeparator(),
-		quit,
-	)
-	desk.SetSystemTrayMenu(menu)
-	w.SetCloseIntercept(func() {
-		// Closing hides the window instead of quitting because scheduler tools are
-		// expected to keep working in the background. The explicit Quit tray item
-		// remains the way to stop the process.
-		w.Hide()
-	})
-}
-
-func acquireSingleInstance(showExisting bool) (net.Listener, bool) {
-	listener, err := net.Listen("tcp", singleInstanceAddress)
-	if err == nil {
-		return listener, true
-	}
-
-	connection, dialErr := net.DialTimeout("tcp", singleInstanceAddress, time.Second)
-	if dialErr == nil {
-		// The first instance listens only on localhost and understands one tiny
-		// command: "show". That keeps the implementation dependency-free and easy
-		// to inspect, which matters more here than introducing a named-pipe or
-		// platform-specific IPC abstraction just to focus an existing window.
-		if showExisting {
-			_, _ = io.WriteString(connection, singleInstanceShowCommand)
-		}
-		_ = connection.Close()
-		return nil, false
-	}
-
-	// If the port is unavailable but does not answer as GoSentry, continue
-	// startup instead of making the application impossible to open because of an
-	// unrelated local listener. In the normal duplicate-start case the dial above
-	// succeeds and this process exits after waking the first instance.
-	return nil, true
-}
-
-func serveSingleInstance(listener net.Listener, w fyne.Window) {
-	if listener == nil {
-		return
-	}
-	go func() {
-		for {
-			connection, err := listener.Accept()
-			if err != nil {
-				return
-			}
-			command, _ := io.ReadAll(io.LimitReader(connection, 32))
-			_ = connection.Close()
-			if strings.TrimSpace(string(command)) != singleInstanceShowCommand {
-				continue
-			}
-			// Accept runs on its own goroutine, so focusing the window must be
-			// marshaled onto the main thread like every other widget update.
-			fyne.Do(func() {
-				w.Show()
-				w.RequestFocus()
-			})
-		}
-	}()
-}
diff --git a/src/ui/singleinstance.go b/src/ui/singleinstance.go
new file mode 100644
index 0000000..59b59f8
--- /dev/null
+++ b/src/ui/singleinstance.go
@@ -0,0 +1,64 @@
+package ui
+
+import (
+	"io"
+	"net"
+	"strings"
+	"time"
+
+	"fyne.io/fyne/v2"
+)
+
+const singleInstanceAddress = "127.0.0.1:37653"
+const singleInstanceShowCommand = "show"
+
+func acquireSingleInstance(showExisting bool) (net.Listener, bool) {
+	listener, err := net.Listen("tcp", singleInstanceAddress)
+	if err == nil {
+		return listener, true
+	}
+
+	connection, dialErr := net.DialTimeout("tcp", singleInstanceAddress, time.Second)
+	if dialErr == nil {
+		// The first instance listens only on localhost and understands one tiny
+		// command: "show". That keeps the implementation dependency-free and easy
+		// to inspect, which matters more here than introducing a named-pipe or
+		// platform-specific IPC abstraction just to focus an existing window.
+		if showExisting {
+			_, _ = io.WriteString(connection, singleInstanceShowCommand)
+		}
+		_ = connection.Close()
+		return nil, false
+	}
+
+	// If the port is unavailable but does not answer as GoSentry, continue
+	// startup instead of making the application impossible to open because of an
+	// unrelated local listener. In the normal duplicate-start case the dial above
+	// succeeds and this process exits after waking the first instance.
+	return nil, true
+}
+
+func serveSingleInstance(listener net.Listener, w fyne.Window) {
+	if listener == nil {
+		return
+	}
+	go func() {
+		for {
+			connection, err := listener.Accept()
+			if err != nil {
+				return
+			}
+			command, _ := io.ReadAll(io.LimitReader(connection, 32))
+			_ = connection.Close()
+			if strings.TrimSpace(string(command)) != singleInstanceShowCommand {
+				continue
+			}
+			// Accept runs on its own goroutine, so focusing the window must be
+			// marshaled onto the main thread like every other widget update.
+			fyne.Do(func() {
+				w.Show()
+				w.RequestFocus()
+			})
+		}
+	}()
+}
diff --git a/src/ui/tray.go b/src/ui/tray.go
new file mode 100644
index 0000000..012e5e7
--- /dev/null
+++ b/src/ui/tray.go
@@ -0,0 +1,40 @@
+package ui
+
+import (
+	"fyne.io/fyne/v2"
+	fynedesktop "fyne.io/fyne/v2/driver/desktop"
+)
+
+func configureSystemTray(a fyne.App, w fyne.Window) {
+	desk, ok := a.(fynedesktop.App)
+	if !ok {
+		// Not every Fyne driver exposes desktop tray features. Returning silently
+		// keeps the same binary usable on platforms or sessions without a tray.
+		return
+	}
+
+	// IsQuit marks this as the tray's quit item. Without it Fyne's
+	// addMissingQuitForMenu appends a second, localized Quit (e.g. "Выход" on a
+	// Russian system) because it only recognizes an existing quit by matching the
+	// localized label — which our literal "Quit" does not. Setting IsQuit makes
+	// Fyne reuse this item instead of adding a duplicate, regardless of locale.
+	quit := fyne.NewMenuItem("Quit", func() {
+		a.Quit()
+	})
+	quit.IsQuit = true
+	menu := fyne.NewMenu("GoSentry",
+		fyne.NewMenuItem("Show", func() {
+			w.Show()
+			w.RequestFocus()
+		}),
+		fyne.NewMenuItemSeparator(),
+		quit,
+	)
+	desk.SetSystemTrayMenu(menu)
+	w.SetCloseIntercept(func() {
+		// Closing hides the window instead of quitting because scheduler tools are
+		// expected to keep working in the background. The explicit Quit tray item
+		// remains the way to stop the process.
+		w.Hide()
+	})
+}