I'm not so familiar with swing, JavaFx all the way
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Anyway, from the screenshot you posted we can't tell that mutch.
You said you tried to remove the components, if you remove the components how is it possible that it's still there.
On what dit you try to set the color, in this case you would have to set the color of the text not of the component the text is in, fyi the color would be transparrent.
And otherwise there still opacity. But I don't think that's the way to go, I wouldn't hide it, I would try to remove it