Display data in a data graphical user interface (GUI) on a display device and display, by a processor, a control GUI on the display device representing the data. The control GUI includes a range defining visual element, corresponding to a data value, that is moveable via input received by the control GUI and defines two ranges of the data. The processor displays indicia associated with the range defining visual element indicating the corresponding data value. The processor receives input from the control GUI indicating the range defining visual element has been moved. In response, the processor visually emphasizes data in the data GUI having data values in a selected one of the defined data range.