Corrected entry: The cosmetology teacher makes marks on Hank's head to show where Luanne cut his hair wrong. She is still holding the blue marker when she walks away. Hank gets up to comfort Luanne, and you can see that he has no marker in his hands. However, when he points out the bumps on his head, he suddenly has a marker and marks them. When the teacher is shown again, she is still holding the blue marker, so she didn't give it to Hank.
King of the Hill (1997)
1 corrected entry in season 1
Starring: Brittany Murphy, Pamela Adlon, Mike Judge, Kathy Najimy, Johnny Hardwick
Bystand Me - S10-E2
Continuity mistake: While Hank, Peggy, and Bobby are asking for help picking up the papers with the dangerous ammonia and bleach recipe, a person in back of the group they are talking to that was originally wearing a dark red hat, red shirt, and blond hair switches to a pink, light blue shirt, and brown hair. A window also suddenly appears behind this individual, where there wasn't one before. (00:17:49 - 00:18:11)
Dale Gribble: Boil up some Mountain Dew. It's gonna be a long night.
More trivia for King of the Hill
To Sirloin with Love - S13-E20
Question: What is Boomhower's occupation?
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.
Correction: There couldn't be another marker lying nearby?
Xofer