A style sheet is incrementally parsed when a change is made. Instead of parsing the entire style sheet text each time a change is made, only a portion of the style sheet is parsed in response to the incremental change. As a result of the incremental parsing the number of data structures needed to be updated upon the incremental change to the style sheet text is minimized. Since only a portion of the data structures are updated, it is possible for other components in software to have smart behavior based on the changes. For example, instead of all the display elements updating their display based on a change to the style sheet, only those dialogs or other parts of the user interface that were showing information about the changed rules need to update their display.