In general you set element properties by means of a number of list boxes, check boxes, radio buttons or text fields you get in the Property Editor. In many cases, it is also possible to set the property values dynamically by a formula. If it is possible, then you can find a formula button beside the corresponding control element. Pushing this button opens the Formula Editor where you can enter your formula for the element property.
The return type of the formula depends on the control element. Look at the following possibilities:

List Box		The formula for a property you set by a list box must return the index of the wanted list box item. Top item has index 0. In given example item 'none' is index 0, item 'Single' is index 1, item 'Double' is 2 etc.
Check Box		The formula for a property you set by a check box must return a boolean (true or false). In case of true check box is selected.
Radio Buttons		The formula for a property you set by radio buttons must return the index of the wanted button. In given example button 'DMY' is index 0 and button 'MDY' is index 1.
Text Field		The formula for a property you set by a text field must return a string.
Color Box		The formula for a color property must return either a color constant or a number that gives the color in the ABGR system. For example wanted color is blue, formula must return blue or 16711680 (0x00FF0000).There are the following color constants: maroon, green, olive, navy, purple, teal, gray, silver, red, lime, yellow, blue, fuchsia, aqua, black and white.

Depending on the status of the property formula, the formula button can have different colors.

	No formula specified.
	Formula specified.
	In this case, mutliple report elements has been selected and for at least one report element was either a different or no property formula specified for this property.

Although font is set by a list box, a formula for a font must return the font name as string (e.g. "Serif").

Rounding is set by a list box, but the property formula does not set the list box index in this case. Instead it sets the index, at which decimal place the rounding should be done. For instance, if you'd like to round to four decimal places, return a 4. If you'd like to round to full thousands, return a -3 which is equal to selecting the '1,000' list item.