diff --git a/apps/opencs/main.cpp b/apps/opencs/main.cpp
index f2e2156865..c7c35a192d 100644
--- a/apps/opencs/main.cpp
+++ b/apps/opencs/main.cpp
@@ -35,6 +35,7 @@ void setQSurfaceFormat()
     format.setSamples(ds->getMultiSamples());
     format.setStencilBufferSize(ds->getMinimumNumStencilBits());
     format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
+    format.setAlphaBufferSize(0);
     QSurfaceFormat::setDefaultFormat(format);
 }