A computer-implemented method for evaluating a plurality of conditional formatting rules applied to a user interface, comprising: providing a plurality of conditional formatting rules (451, 453, 541, 542, 543), each of the plurality of conditional formatting rules having an associated formatting type; identifying a conditional formatting rule of the plurality of conditional formatting rules for evaluation; for said identified conditional formatting rule, identifying a range of data cells contained in the user interface associated with the identified conditional formatting rule, for each cell within the range of cells: determining if the identified conditional formatting rule is satisfied for the data cell by checking if a condition supplied with the identified conditional formatting rule evaluates to true; determining if the formatting type associated with the identified conditional formatting rule conflicts with a formatting type previously applied or determined as having to be applied to the data cell; if it is determined that the formatting type associated with the identified conditional formatting rule does not conflict with a formatting type previously applied or determined as having to be applied to the data cell, applying the formatting type associated with the identified conditional formatting rule to the data cell; and if it is determined that the formatting type associated with the identified conditional formatting rule does conflict with a formatting type previously applied or determined as having to be applied to the data cell, not applying the formatting type associated with the identified conditional formatting rule to the data cell; and determining if additional conditional formatting rules are to be evaluated and recursively identifying and evaluating (705, 709, 711, 713) said additional conditional formatting rules. providing a plurality of conditional formatting rules (451, 453, 541, 542, 543), each of the plurality of conditional formatting rules having an associated formatting type; identifying a conditional formatting rule of the plurality of conditional formatting rules for evaluation; for said identified conditional formatting rule, identifying a range of data cells contained in the user interface associated with the identified conditional formatting rule, for each cell within the range of cells: determining if the identified conditional formatting rule is satisfied for the data cell by checking if a condition supplied with the identified conditional formatting rule evaluates to true; determining if the formatting type associated with the identified conditional formatting rule conflicts with a formatting type previously applied or determined as having to be applied to the data cell; if it is determined that the formatting type associated with the identified conditional formatting rule does not conflict with a formatting type previously applied or determined as having to be applied to the data cell, applying the formatting type associated with the identified conditional formatting rule to the data cell; and if it is determined that the formatting type associated with the identified conditional formatting rule does conflict with a formatting type previously applied or determined as having to be applied to the data cell, not applying the formatting type associated with the identified conditional formatting rule to the data cell; and determining if the identified conditional formatting rule is satisfied for the data cell by checking if a condition supplied with the identified conditional formatting rule evaluates to true; determining if the formatting type associated with the identified conditional formatting rule conflicts with a formatting type previously applied or determined as having to be applied to the data cell; if it is determined that the formatting type associated with the identified conditional formatting rule does not conflict with a formatting type previously applied or determined as having to be applied to the data cell, applying the formatting type associated with the identified conditional formatting rule to the data cell; and if it is determined that the formatting type associated with the identified conditional formatting rule does conflict with a formatting type previously applied or determined as having to be applied to the data cell, not applying the formatting type associated with the identified conditional formatting rule to the data cell; and determining if additional conditional formatting rules are to be evaluated and recursively identifying and evaluating (705, 709, 711, 713) said additional conditional formatting rules.