When you try to display a field with negative content on a screen, you can run into the error : "FX015: Sign lost." As a solution you could change the I/O template for the field from "____________" to "___________V" (with +/- sign). Althoug SAP tells "... The template of an input/output field on a screen may only consist of underscores. At runtime, this is replaced with a suitable template (for example, for entering a date). "(message 620(37)), you can change the template, eg. for negativ values (V) and separators.