If a subtraction feature, like a hole or pocket, is the first feature in a body, then it will be represented as a solid on the screen until it is assembled with another body.
You can verify what Mark suggested by looking at the icon in front of the Body containing your Pocket. If there is a little yellow minus symbol behind the gear, Pads and Pockets are created as negatives (Pockets and Pads). If the yellow symbol is a +, or there is no symbol, Pads and Pockests are created normally.
The polarity of the Body is determined by the first feature, as Mark said.
