In the late 1990s the first reasonably powerful WYSIWYG editors arrived on the market, which meant Web designers no longer needed a technical understanding of HTML to build web pages. Such editors indirectly encouraged extensive use of nested tables to position design elements. As designers edited their documents in these editors, unnecessary code and empty elements were added to the document. Furthermore, unskilled designers were likely to use tables more than required when using a WYSIWYG editor. This practice frequently led to many tables nested within tables, as well as tables with unnecessary rows and columns. The use of graphic editors with slicing tools that output HTML and images directly also promoted poor code with tables often having many rows of 1 pixel height or width. Sometimes many more lines of code were used to render content than the actual content itself.