Continuity mistake: When Uncle Buck and Tia are talking in the car after Uncle Buck kidnapped Bug, the first 5-6 shots show a red box and some envelopes near the windshield. In the next shot there are two envelopes near the windshield, no red box.
Suggested correction: The camera moves over to the middle of the car. If you look to the right edge the red box is still there. Maybe a square screen TV won't show it.
Suggested correction: In the first few shots the camera is positioned in front of Buck - note the rear view mirror is on the left of the image. The later shots are with the camera positioned in the middle - note the rear view mirror is now centered. Part of the red box is visible on the far right in the later shots, and the envelope that was on the left is now center right.
Continuity mistake: When Buck is doing laundry, he takes a plate of clothes out of the oven and sits it in front of him. After the shot of him burning himself, the plate has disappeared.