Help Questions when connected via USB


Hi, I am new to the group and android in general. I am coming from a HTC TP2 phone. I don't know if this is a bug or normal. When I connect my droid to the computer via usb, I cannot do anything on the phone. The screen does not respond at all. If I connect my droid to an usb charger line, it works OK. If I connect the charger line to a standard dock and connect the phone: I get the choice to pick an application to launch (Bedside, Productivity). It won't respond to screen selections. Sometimes the home key responds.
Are these normal? My windows mobile did not have this issue. I like the android so far except for a couple of issues like this.