diff --git a/+sample/dummy_GUI.m b/+sample/dummy_GUI.m
index 2bc4ab6..607db83 100644
--- a/+sample/dummy_GUI.m
+++ b/+sample/dummy_GUI.m
@@ -13,7 +13,7 @@ function Plot(this, src, data)
                 features = [features; currentBest.Features];
             end
             
-            if(isnan(this.Handle))
+            if(isequaln(this.Handle, NaN))
                 this.Handle = figure;
             end
             figure(this.Handle);