To dream that you are in an enclosure, indicates that you are in defensive mode. Some situation in your waking life has put you on guard and arouses the need to protect/defend yourself.
To dream that you are in an enclosure that is shrinking, indicates that you feel restrained and confined in some circumstance. It represents actual or perceived limitations. You need to start testing out your boundaries in order to grow.
To dream that you are in an enclosure made of glass, suggests that you are too critical about a person or situation.