Doing a flush every frame caused a crash in certain cases; only do it when necessary.

src/common/FBBackendSDL.cxx

@@ -698,15 +698,17 @@ void FBBackendSDL::clear()
 {
   ASSERT_MAIN_THREAD;
 
-  // SDL3 Metal: flush before clear so any preceding GEOMETRY commands land in
-  // their own command queue.  METAL_RunCommandQueue does not reset the texture
-  // statecache on CLEAR, so a subsequent GEOMETRY with the same scale/address
-  // mode skips sampler re-binding on the freshly-created encoder → Metal API
-  // Validation abort.  Flushing here guarantees a fresh statecache after CLEAR.
-  SDL_FlushRenderer(myRenderer);
   SDL_RenderClear(myRenderer);
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void FBBackendSDL::flush()
+{
+  ASSERT_MAIN_THREAD;
+
+  SDL_FlushRenderer(myRenderer);
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void FBBackendSDL::detectFeatures()
 {

src/common/FBBackendSDL.hxx

@@ -136,6 +136,7 @@ class FBBackendSDL : public FBBackend
       Clear the frame buffer.
     */
     void clear() override;
+    void flush() override;
 
     /**
       This method is called to query and initialize the video hardware

src/emucore/FBBackend.hxx

@@ -85,6 +85,14 @@ class FBBackend
     */
     virtual void clear() = 0;
 
+    /**
+      Flush pending render commands without presenting.  Used to ensure a
+      clean command-queue boundary before clear() in dialog rendering, so
+      any preceding geometry from the previous frame lands in its own
+      command queue rather than sharing a queue with the subsequent clear.
+    */
+    virtual void flush() = 0;
+
     /**
       Updates window title.
 

src/emucore/FrameBuffer.hxx

@@ -383,6 +383,7 @@ class FrameBuffer
       Clear the framebuffer.
     */
     void clear() { myBackend->clear(); }
+    void flush() { myBackend->flush(); }
 
     /**
       Transform from window to renderer coordinates, x/y direction.

src/gui/DialogContainer.cxx

@@ -127,8 +127,10 @@ void DialogContainer::render()
 #endif
 
   // Make sure we start in a clean state (with zero'ed buffers)
-  if(!myOSystem.eventHandler().inTIAMode())
+  if(!myOSystem.eventHandler().inTIAMode()) {
+    myOSystem.frameBuffer().flush();
     myOSystem.frameBuffer().clear();
+  }
 
   // Render all dialogs
   myDialogStack.applyAll([&](Dialog*& d) {