When Roseanne takes David from Darlene's apartment she tells him that she threw all his stuff outside. This is after David and Darlene arrived at the apartment, after having been away for enough time for Mark and Roseanne to show up, and dump David's things. This would lead one to expect that Darlene and David would have noticed David's things scattered outside the apartment and not be surprised to find Roseanne waiting for them in the apartment.
When Mark is putting his jacket on, the collar is laying properly around his neck. In the next frame, the collar is stuck under the shoulder of his jacket, as he walks out the door.
Mark can be heard muttering the word "f***" under his breath in Roy's apartment.
The Conners live in Fulton County, which is in southern IL. Roseanne told Dan she had to drive to Rockford to pick up David from the bus station. Rockford is in northern Illinois. If David was to come from his mother's in Michigan, he would've taken the bus to a city much closer, such as Chicago.
When Becky walks into the kitchen for the second time, the microphone appears from above.