In a large skillet melt butter over high heat. Add onions, reduce heat and saute for about 5 minutes or somewhat soft.
Add rest of vegetables, 1 teaspoon salt and 1 teaspoon sugar. Saute for a minute, cover skillet lower heat and simmer for 5 minutes until tender, but still crisp.
Uncover skillet, raise heat, add lime juice and evaporate all liquid until vegetables are slightly syrupy and glazed. Adjust the seasoning if necessary.