Sean,

Thanks for the response!
Now you touched in a subject I was investigating some time ago and I thought it was some imagination of my mind <s>.
The case is exactly this! My value on the ControlSource and Value properties are 0.000, however if I "browse" the table, the corresponding field is blank (not NULL!). In order to solve my problem, I could do the following:

1) In the WHEN method of the textBox:

IF EMPTY(THIS.Value)
  REPLACE MyTable.MyField WITH 0.0000 IN MyTable
ENDIF

This solution may take too much effort to implement in my application...

2) When I APPEND BLANK the new record:

SELECT MyTable
APPEND BLANK
SCATTER MEMVAR MEMO
GATHER MEMVAR MEMO    && This action puts the zeroes into the numeric fields

This Solution may take less time to implement, but it's undesirable yet.

Do you know it is a known bug? Is there any workaround?
Thank you!