diff --git a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/CyberCoreDesktopApplication.java b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/CyberCoreDesktopApplication.java
index aeaf492..397a28e 100644
--- a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/CyberCoreDesktopApplication.java
+++ b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/CyberCoreDesktopApplication.java
@@ -130,6 +130,10 @@ public class CyberCoreDesktopApplication extends Application {
         mainAppView.setOnCertificates(() -> new CertificatesManagerDialog(primaryStage, certificateManager).show());
         mainAppView.setOnAbout(() -> openAboutDialog(primaryStage));
 
+        // Exibe imediatamente a janela principal em primeiro plano para o usuário
+        mainAppView.show();
+        logger.info("Janela principal JavaFX exibida.");
+
         // Inicializa o servidor local do protocolo CCSP/1 para atender requisições do navegador
         initCcspServer(primaryStage);
 
@@ -140,11 +144,8 @@ public class CyberCoreDesktopApplication extends Application {
         this.systemTrayManager = new SystemTrayManager(primaryStage, this::refreshCertificates);
         this.systemTrayManager.setup();
 
-        // Carrega os certificados instalados na máquina do usuário
-        refreshCertificates();
-
-        mainAppView.show();
-        logger.info("Janela principal JavaFX exibida.");
+        // Carrega os certificados instalados na máquina em segundo plano para não congelar a interface
+        CompletableFuture.runAsync(this::refreshCertificates);
     }
 
     private void refreshCertificates() {
diff --git a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/tray/SystemTrayManager.java b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/tray/SystemTrayManager.java
index 07869b0..fc4e557 100644
--- a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/tray/SystemTrayManager.java
+++ b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/tray/SystemTrayManager.java
@@ -15,6 +15,8 @@ import java.awt.PopupMenu;
 import java.awt.RenderingHints;
 import java.awt.SystemTray;
 import java.awt.TrayIcon;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
 import java.awt.image.BufferedImage;
 import java.util.Objects;
 
@@ -76,7 +78,17 @@ public class SystemTrayManager {
             this.trayIcon = new TrayIcon(iconImage, "CyberCore Signer (CCSP/1 Ativo)", popup);
             this.trayIcon.setImageAutoSize(true);
 
-            // Clique no ícone restaura a janela
+            // Clique com o botão esquerdo (single-click) restaura a janela imediatamente
+            this.trayIcon.addMouseListener(new MouseAdapter() {
+                @Override
+                public void mouseClicked(MouseEvent e) {
+                    if (e.getButton() == MouseEvent.BUTTON1) {
+                        Platform.runLater(SystemTrayManager.this::showStage);
+                    }
+                }
+            });
+
+            // Duplo clique ou acionamento nativo padrão também restaura a janela
             this.trayIcon.addActionListener(e -> Platform.runLater(this::showStage));
 
             tray.add(this.trayIcon);
@@ -104,10 +116,31 @@ public class SystemTrayManager {
     }
 
     public void showStage() {
-        if (stage != null) {
-            stage.show();
-            stage.setIconified(false);
+        if (stage == null) {
+            return;
+        }
+
+        try {
+            if (!stage.isShowing()) {
+                stage.show();
+            }
+
+            if (stage.isIconified()) {
+                stage.setIconified(false);
+            }
+
             stage.toFront();
+            stage.requestFocus();
+
+            // No Windows (Win32 / DWM), chamadas de toFront() partindo da bandeja do sistema
+            // podem ser suprimidas por políticas de foco do SO (Foreground Lock Timeout).
+            // A elevação momentânea via setAlwaysOnTop força o gerenciador de janelas a trazer
+            // o assinador diretamente para o primeiro plano.
+            stage.setAlwaysOnTop(true);
+            stage.setAlwaysOnTop(false);
+
+        } catch (Throwable t) {
+            logger.debug("Falha secundária ao restaurar stage da bandeja: {}", t.getMessage());
         }
     }
 
diff --git a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/view/MainAppView.java b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/view/MainAppView.java
index e6c4d4f..4b15621 100644
--- a/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/view/MainAppView.java
+++ b/modules/cybercore-ui/src/main/java/br/com/cybercore/signer/ui/view/MainAppView.java
@@ -297,8 +297,17 @@ public final class MainAppView {
 
     public void show() {
         stage.centerOnScreen();
+        if (stage.isIconified()) {
+            stage.setIconified(false);
+        }
         stage.show();
         stage.toFront();
+        stage.requestFocus();
+        try {
+            stage.setAlwaysOnTop(true);
+            stage.setAlwaysOnTop(false);
+        } catch (Throwable ignored) {
+        }
     }
 
     public void hide() {
diff --git a/modules/cybercore-ui/src/test/java/br/com/cybercore/signer/ui/tray/SystemTrayManagerTest.java b/modules/cybercore-ui/src/test/java/br/com/cybercore/signer/ui/tray/SystemTrayManagerTest.java
new file mode 100644
index 0000000..644b0e3
--- /dev/null
+++ b/modules/cybercore-ui/src/test/java/br/com/cybercore/signer/ui/tray/SystemTrayManagerTest.java
@@ -0,0 +1,29 @@
+package br.com.cybercore.signer.ui.tray;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.awt.SystemTray;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+@DisplayName("Testes do Gerenciador de Bandeja (SystemTrayManager)")
+class SystemTrayManagerTest {
+
+    @Test
+    @DisplayName("Deve rejeitar Stage nulo no construtor")
+    void shouldRejectNullStage() {
+        assertThatThrownBy(() -> new SystemTrayManager(null, () -> {}))
+                .isInstanceOf(NullPointerException.class)
+                .hasMessageContaining("stage must not be null");
+    }
+
+    @Test
+    @DisplayName("Deve reportar suporte do ambiente ou lidar graciosamente sem UI nativa")
+    void shouldReportSupportOrHandleGracefully() {
+        boolean supported = SystemTray.isSupported();
+        // Verifica que chamada não lança exceção fatal
+        assertThat(supported).isIn(true, false);
+    }
+}