diff --git a/src/qglview_test/qglview_window.cpp b/src/qglview_test/qglview_window.cpp
index 3d400a4..1326b33 100644
--- a/src/qglview_test/qglview_window.cpp
+++ b/src/qglview_test/qglview_window.cpp
@@ -35,6 +35,7 @@ public:
 	void reloadShaders() { QGLEngineShaders::loadShadersMulti(mys, "test1.glsl"); }
 	void draw() {
 		if (!mys) return;
+		if (!mys->isLinked()) return;
 		auto planes = getFreePlanes(1);
 		bindPreviousOutput(0);
 		// bindDeferredBuffer(Renderer::dbrNormalZSolid, 1);