diff --git a/dgl/src/WindowPrivateData.cpp b/dgl/src/WindowPrivateData.cpp
index 5ed30ba6..302d3ac4 100644
--- a/dgl/src/WindowPrivateData.cpp
+++ b/dgl/src/WindowPrivateData.cpp
@@ -303,6 +303,7 @@ void Window::PrivateData::hide()
 void Window::PrivateData::close()
 {
     DGL_DBG("Window close\n");
+    // DGL_DBGp("Window close DBG %i %i %p\n", isEmbed, isClosed, appData);
 
     if (isEmbed || isClosed)
         return;
@@ -531,6 +532,9 @@ void Window::PrivateData::onPuglFocus(const bool focus, const CrossingMode mode)
 {
     DGL_DBGp("onPuglFocus : %i %i\n", focus, mode);
 
+    if (isClosed)
+        return;
+
     if (modal.child != nullptr)
         return modal.child->focus();
 
diff --git a/tests/Makefile b/tests/Makefile
index 7c6e2d30..66d5f84e 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -33,7 +33,7 @@ ifeq ($(HAVE_STUB),true)
 UNIT_TESTS   += Window.stub
 endif
 ifeq ($(HAVE_VULKAN),true)
-UNIT_TESTS += Window.vulkan
+UNIT_TESTS   += Window.vulkan
 endif
 
 MANUAL_TARGETS = $(MANUAL_TESTS:%=../build/tests/%$(APP_EXT))
@@ -144,5 +144,9 @@ clean:
 -include ../build/tests/Demo.cpp.cairo.d
 -include ../build/tests/Demo.cpp.opengl.d
 -include ../build/tests/Demo.cpp.vulkan.d
+-include ../build/tests/Window.cpp.cairo.d
+-include ../build/tests/Window.cpp.opengl.d
+-include ../build/tests/Window.cpp.stub.d
+-include ../build/tests/Window.cpp.vulkan.d
 
 # ---------------------------------------------------------------------------------------------------------------------
diff --git a/tests/tests.hpp b/tests/tests.hpp
index c9b8b0cc..334dd1fe 100644
--- a/tests/tests.hpp
+++ b/tests/tests.hpp
@@ -49,6 +49,7 @@ private:
     void run() override
     {
         d_sleep(numSecondsToWait);
+        d_stdout("About to quit now...");
         app.quit();
     }
 };