There is a work around that works with some graphics cards, so may work for you:
Open the app bundle (right click on OpenRA.app, then "Show Package Contents") and open the file Contents/Resources/shaders/chrome-rgba.fx with a text editor.
Near the bottom of the file you should see
Code: Select all
technique high_quality {
pass p0 {
BlendEnable = true;
DepthTestEnable = false;
CullFaceEnable = false;
VertexProgram = compile latest Simple_vp();
FragmentProgram = compile latest Simple_fp();
BlendEquation = FuncAdd;
BlendFunc = int2( SrcAlpha, OneMinusSrcAlpha );
}
}