- UH-OH. There's trouble in paradise. ABC's "Roseanne," the top-rated new show this season and the top-rated show - period - for the past two weeks, is experiencing . . . shall we say, "Growing Pains."

And the question is, "Who's the Boss?"Matt Williams, one of three executive producers on the sitcom, has left the show over what he called "creative tensions" "between the executive producers and Roseanne Barr." Reportedly, Barr and Williams have had some serious differences over the nature of the blue collar character she plays on the show and the direction of certain storylines.

Sources close to the show acknowledge that Barr has strong opinions about the show and is quick to express her feelings. OK, OK - they said she can sometimes be difficult. "But it's her show," one insider told me Monday. "She created this character. She knows it better than anyone else. Why shouldn't she fight for it?"

That opinion was evidentially shared by the show's other two producers, Marcy Carsey and Tom Werner. They released a statement of their own saying that Barr had been given creative control over her own character, and that her insight into working women and housewives is what helped to make the show so appealing to the American public.

Gee - do you think their experience with "The Cosby Show" taught Carsey and Werner anything about trusting the instincts of a comedian who the American public seems to be responding to?

- FOX TELEVISION, which is beginning to clear a profit after several years of being a drain on owner Rupert Murdoch's cash flow, is adding a third night of programming to their weekly schedule in September. Fox chairman Barry Diller told the annual meeting of Fox affiliates on Saturday that the fledgling "fourth network" will branch out into Mondays this fall.

"Fox has come a long way in two years," said the service's board of governors chairman Michael Fisher. "We are undeniably a force to be reckoned with in the industry. I'm excited about going to Monday and can't wait until we get a fourth night."

A fourth night? KSTU, the Utah Fox affiliate, hasn't even added the second night yet. But with the success of "Married . . . With Children" and "America's Most Wanted" on Sundays, you can bet Ch. 13 will be trying to find a way to stick with Fox on Saturdays and Mondays.

- THREE NEW LATE-NIGHT television programs have premiered recently. It's probably a little too early to pass judgment on the shows at this point. But it's not too late to offer a few suggestions on how the shows might be improved so they can last long enough to warrant a full-scale review.

- To Pat Sajak, host of CBS's new "Pat Sajak Show" (weeknights at 11:05 p.m., Ch. 5): Shorten the guest list. I know that 90 minutes is a lot of time to fill, but one can only take so many superficial interviews in one sitting. You had some good guests in your premiere episode on Monday, and you asked some good questions. But come on - four minutes with Chevy Chase? Three minutes each with Peter Ueberoth, Michael Gross, Joan Van Ark and the Judds? Cut back the guest list, shorten the couch and double your time with the good guests, and I think you'll have an entertainment/talk program that truly is unique - and worth watching.

- To Arsenio Hall, host of "The Arsenio Hall Show" (Weeknights at 11 p.m., Ch. 13): Get your audience under control. It's clear you're going for a young, hip, upscale following. And it's equally clear that your audience loves you - either that, or your studio warm-up man is whipping them into a fevered frenzy. But they are so enthusiastic and so boisterous that they are getting in the way. They aren't allowing you to do your thing freely or to interview your guests intelligently, and they're giving your show an obnoxious, self-congratulatory air that's sort of a turn off to those who are watching back home. Rein 'em in, Arsenio, before they stampede your ratings.

- To David Frost, host of "Inside Edition" (Weeknights at 11:05 p.m., Ch. 4): Lighten up. You're trying so hard to not look like "tabloid television" that you're coming across with too much smug self-righteousness. It's as if you're not really sure if this new syndicated news magazine is worth doing, and you're trying to convince yourself while you convince us. Just play the stories straight and let us affix our own determination of worth on them. And don't be afraid to have fun with the fun ones. Heaven knows, we critics will.

- ERIC IDLE, Monty Python alum who will star as a ghost in NBC's upcoming "Nearly Departed" series, on the secret of Monty Python's success: "We had only one rule - if we laughed at it, it was in."

- SONNY STEELGRAVE is returning to CBS-TV's "Wiseguy." Fans of the series will wonder how that can be, since the gangster (played brilliantly by Ray Sharkey) electrocuted himself on the series last season. But creator Stephen Cannell confirmed that Sharkey will be back as Steelgrave later this season in a series episode in which "Wiseguy" Vinnie (Ken Wahl) spends a little time in a mental hospital. Sonny, of course, will appear in a dream sequence.

- ONE OF THE ALL-TIME GREAT television specials will return to the air March 24 when NBC presents the original TV production of "Peter Pan" starring Mary Martin.

Also upcoming for NBC: - Night of 1,000 Laughs, a full evening of prime time sitcoms, including fresh episodes of "The Cosby Show," "ALF," "Cheers," "Empty Nest," "Golden Girls" and "Night Court." Not only will this provide counter-programming for CBS's acclaimed miniseries, "Lonesome Dove," but it will also serve as an experiment at running comedy in the 9-10 p.m. time period - something NBC, with its embarrassing sitcom wealth, is considering for next fall; - A TV-movie based on the controversial - and suddenly in the news again - Rowe vs. Wade court decision; - A four-hour miniseries version of "The Phantom of the Opera," scheduled to air next December.