Have you noticed the colours when the concurrent requests are submitted?

Green when it is in pending or running status
Yellow for warning
Red for the errors

Do you know these colours are controlled by a profile called FND: Indicator Colors. If you se the value to Yes, you will these colors, if you say No, you will see no colors. Also I noticed, the prameters that are required while submiting the concurrent program usually show up in Yello color (standard for required fields). If you set this profile value to No, even they are becoming white.

Try it and feel the effect !