>hi, again with this problem that has me that my head hurts so much thinking and look for solution.
>I have 3 combobox (brands, models, sub-models) of which one depends on the other.
> a brand has several models and a model has several submodels level table I related
>the problem is when I save a record with a brands, model and submodel when I try to modify combos models and submodels change value, for the reason that I'm doing a set filter in the GotFocus brand models and sub-models of the model

Don't use SET FILTER in combos. Here's my suggestion for how to handle this kind of related combos:

http://www.tomorrowssolutionsllc.com/Articles/Cascading%20combos%20and%20lists.PDF

Tamar