I did this and there is nothing rendered (except "test"). Text rendered
@Override
public void render(int p_render_1_, int p_render_2_, float p_render_3_) {
for(int i = 0; i < this.buttons.size(); ++i) {
this.buttons.get(i).render(p_render_1_, p_render_2_, p_render_3_);
}
Minecraft mc = Minecraft.getInstance();
mc.fontRenderer.drawStringWithShadow("TEST",0,0,0xFFFFFF);
AbstractGui.fill(100,100,100,100,100);
}