When designing a form in character cell units, all object dimensions and position coordinates are expressed in character cells represented as whole numbers. Oracle Forms will only accept whole numbers for size and position properties and will round up to the next integer. For example, if the width property value of a text item is set to 12.5 character cells, Oracle Forms will round up the Width property value to 13 character cells automatically.
When Coordinate System is set to Character Cell, the Character Cell Width/Height properties show the actual size of a character cell in the current real units. This character cell size is based on the size of the default font on the design time device, and the Character Cell Width/Height property values cannot be edited.
Working in the Layout Editor with character cell units can produce unexpected results, particularly when using the mouse to draw and position items, graphic text, and images. Using character cells effectively produces a "snap-to-grid" effect, with the grid increments being the size of a character cell.
About converting coordinate system units
Specifying the coordinate system
About using the real units coordinate system