Related Pop-Up menues loose it when I click on form
i have three tables
1) a distinct Category table with only about 15 records.
2) a Sub-Category table with about 40 records
3) an Inventory table with hundreds of records.
I have a Pop-up menu that selects one of the 15 categories.
When I select a category and click on a second pop-up menu it is correctly populated with
only the related sub-categories AND simutainously a portal is crrrectly populated with the related items in Inventory.
So all is working and seems well ! yeah!
However if i click on anything other than one of the two pop-up menues or the Portal,
The Top field in the Category Pop-up menu blanks out and the Sub Category pop-up menu says <no values defined> when i click on it.
After some time of experimentation i noticed that the first record in the Category table is for some reason replaced with
what ever the last category i clicked on and at that point it looses its relation with the Sub category table.
Simple question... How can i prevent this replacement? ....Thanks very much