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jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglOffscreenBuffer.java

@@ -31,6 +31,7 @@
  */
 package com.jme3.system.lwjgl;
 
+import com.jme3.system.AppSettings;
 import com.jme3.system.JmeContext;
 
 /**
@@ -41,4 +42,12 @@ public class LwjglOffscreenBuffer extends LwjglWindow {
     public LwjglOffscreenBuffer() {
         super(JmeContext.Type.OffscreenSurface);
     }
+
+    @Override
+    protected void showWindow() {
+    }
+
+    @Override
+    protected void setWindowIcon(final AppSettings settings) {
+    }
 }

jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglWindow.java

@@ -315,18 +315,20 @@ public abstract class LwjglWindow extends LwjglContext implements Runnable {
             glfwSwapInterval(0);
         }
 
-        if(type != Type.OffscreenSurface) {
         setWindowIcon(settings);
-            glfwShowWindow(window);
-        }
+        showWindow();
 
         allowSwapBuffers = settings.isSwapBuffers();
     }
 
+    protected void showWindow() {
+        glfwShowWindow(window);
+    }
+
     /**
      * Set custom icons to the window of this application.
      */
-    private void setWindowIcon(final AppSettings settings) {
+    protected void setWindowIcon(final AppSettings settings) {
 
         final Object[] icons = settings.getIcons();
         if (icons == null) return;