Dexter had no connection with Velma whatsoever

I watched that interstitial on Cartoon Network as a kid in the early 2000s.

I still watched them

When Cartoon Network started 24 hours a day in my country on July 1, 2001 Sunday, I watched reruns of original shows such as Dexter's Laboratory, Cow and Chicken & I Am Weasel. However, Dexter's Lab got new episodes on Cartoon Network between 2002 & 2004. In the mid 2000's, I can still watch Cow and Chicken & I Am Weasel on Cartoon Network when they're still in reruns. As of today, Dexter's Laboratory is the only Cartoon Network original that I could always remember.

The first Dexter's Lab movie that I just watched

I watched that movie a lot on Cartoon Network because I love Dee Dee more than Dexter before the 23rd episode of Dexter's Laboratory Season 5.