Gripes have mounted recently over support in IE 6 for Cascading Style Sheets (CSS), a Web standard increasingly important to design professionals. Web developers and makers of Web authoring tools say the software giant has allowed CSS bugs to linger for years, undermining technology that promises to significantly cut corporate Web site design costs.

Seeking to goad Microsoft into action, digital document giant Adobe Systems last week unveiled a deal to bolster support for CSS in its GoLive Web authoring tool with technology from tiny Web browser maker Opera Software, whose chief technology officer first proposed CSS nine years ago. Opera maintains an active role in developing CSS through the World Wide Web Consortium (W3C).

But standards advocates said it was unclear whether Adobe's action could prod Microsoft into better CSS support, given the lack of browser competition.

"Because it owns the marketplace, Microsoft's under very little pressure to fix remaining IE 6 bugs," said Jeffrey Zeldman, an independent Web developer and cofounder of the Web Standards Project. "When it formed this partnership with Opera, Adobe may have wanted to light a fire under IE, but lots of people have wanted to do that and have not been able to."