>Yes, I have used AddProperty but that's not good solution. I have code in application that uses loop of Objects collection of Custom class, and when I used AddProperty Objects collection always stays empty, so I must find better solution.

If you are using VFP 8, you can use the new Collection class. If not then you can use your Custom property and store a reference to each form in an array property. Instead of looping through the Objects collection, you could loop through the array.

HTH.