Everything was calm and peaceful in the early days of the Laurel Green Condominiums in Arlington. All 20 garden apartment units were picture-perfect, each with its sleek contemporary design and color-coordinated front door.

All that ended last year when condominium owner Mireille R. Alberti decided to redesign her unit. She replaced that time-honored standby of contemporary architecture -- the sliding glass door on the front of her home -- with what her neighbors say is a "Dutch colonial" bay window.

The resulting legal battle over that window, which cost Alberti $1,500 to install, has dragged on for 15 months and is now on appeal to the Virginia Supreme Court. It is estimated that legal costs to Alberti and her neighbors have surpassed the $17,000 mark and are still climbing.

"Everybody is mad about this," said one Laurel Green resident who asked not to be quoted by name because of the "endless aggravation" the case had caused her. "It's gotten so bad that we all hate to come home any more."

Alberti, a French immigrant who runs a reweaving shop in Arlington, portrays herself as a crusader for the cause of free expression in a regimented world. "I think we live in a free country and I don't think people can be pushed around," she says. "I can afford to fight this, but let's face it: how many other people could afford it?"

But Alberti's neighbors argue she signed away her rights to independently redesign her home when she moved into the development. The condominium association's bylaws prohibit major exterior changes without the express permission of the group's board of directors.

"We're fighting for the principle here," says Douglas Nichols, a member of the condominium association. "You can't do anything you want in your home if you live in a condominium. You have to consult the other homeowners."

Nichols acknowledges that Alberti's bay window, a box-like affair with an overhanging metal roof, "really doesn't look that bad." But it damages the "architectural integrity" of the contemporary complex, he said. And residents concluded that they had to contest it if they were to retain their right to limit design changes.

Clouds began gathering on the Laurel Green horizon early last year when Alberti decided to fix a troublesome water leak in the frame around her sliding glass door. She says several contractors told her the door had been improperly installed, and that the leak could only be eliminated if she replaced the door with a stationary window.

But when she embarked upon the change, which she thought would improve the value of her home, she met widespread criticism from her neighbors. Attempts to negotiate a settlement failed; Alberti completed the window, and her neighbors took her to court.

"All she would have had to do was ask for approval," said Nicholas. "We weren't really out to get the old lady."

Arlington Circuit Judge Paul D. Brown ruled against Alberti this spring, noting in his decisioin, "The case is getting out of proportion to what is involved here." He ordered her to restore the original sliding door, replace some siding she had installed around the door, and pay $4,000 of her neighbors' legal bills. That order has since been stayed while Alberti appeals her case to the state Supreme Court.

Alberti concedes she did not formally seek the approval of the condominium board for her window, and that she had not even read the group's bylaws at the time she had the window built. But she maintains other residents in the tiny complex had made changes to individualize their units without seeking board approval, including changing their house numbers and storm doors.

"Nobody ever told me I had to ask them," she says. 'I don't think that is fair."

With tensions running high in the quiet little townhouse complex, Alberti's window now stands as a mute reminder of thousands of dollars both sides have spent to defend their principles. But it seems unlikely that either side will let the expense keep them from slugging it out to the end.

"I'm not going to let them win," Alberti says.