As in VFP help for =Command:
*---------------------
= Expression1 [, Expression2 ...]
The = command evaluates one or more expressions, Expression1, Expression2 ..., and discards the return values. This option is particularly useful when a Visual FoxPro function or a user-defined function has a desired effect, but there is no need to assign the function's return value to a variable, array element, or field.
.....
If only one expression (Expression1) is included, the equal sign is optional.
*--------------------------------

See also VFP Help on = OPERATOR.

>I have some limited understanding of the use of the equal sign in the property sheet. For instance, I know how to create a mult-line caption by setting the caption property to

='abc'+chr(13)+'def'

>Now, I've never seen any documentation on this feature, so I have a few questions. What are the limitations on what I put after the equal sign? When is it evaluated? Which of the following, if any, make sense?

=m.SomeVariable
>=clr_Purple && where clr_Purple is #defined in an include file
>=SomeUDF(...)
>

>
>Thanks in advance,