fix: Canvas locking when using waitFor (AWT + lwjgl3)

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

@@ -552,7 +552,7 @@ public void run() {
                 // All this does is call swapBuffers().
                 // If the canvas is not active, there's no need to waste time
                 // doing that.
-                if (renderable.get() && canvas.hasContext()) {
+                if (renderable.get() && canvas.hasContext() && canvas.isValid()) {
                     try {
                         if (allowSwapBuffers && autoFlush) {
                             // calls swap buffers | lock, etc.
@@ -646,6 +646,18 @@ public void create(boolean waitFor) {
         this.contextFlag.set(true);
     }
 
+    /**(non-Javadoc)
+     * @param createdVal boolean
+     */
+    @Override
+    protected void waitFor(boolean createdVal) {
+        // AWT together with LWJGLX cannot handle waitFor() in the best way,
+        // since the context is created on the fly.
+        if (createdVal) {
+            LOGGER.log(Level.WARNING, "create(true) is not supported for AWT!");
+        }
+    }
+
     /**
      * (non-Javadoc)
      * @see com.jme3.system.lwjgl.LwjglWindow#destroyContext() 
@@ -716,6 +728,10 @@ protected void createContext(AppSettings settings) {
         canvas.createContext();
         canvas.makeCurrent();
 
+        SwingUtilities.invokeLater(() -> {
+            canvas.validate();
+        });
+
         // This will activate the "effective data" scrubber.
         if (settings.getBoolean("GLDataEffectiveDebug")) {
             LOGGER.log(Level.INFO, "[ DEBUGGER ] :Effective data to initialize the LWJGL3-AWT context\n{0}",