Records Forgetting Data From Cascading Combo After Navigating Away

Hi all, complete Access n00b here requiring some assistance if possible with the dreaded cascading combos. Would appreciate any help I can get. I've tried searching but can't find this particular problem mentioned (am probably searching for the wrong thing, but anyway...) Here is my situation:

I have a form [Component] with a simple cascading combo box scenario [cboCategory] and [cboSubcategory].

[cboCategory] has as its row source -
SELECT tblCategory.categoryid, tblCategory.Category FROM tblCategory ORDER BY tblCategory.Category;

Control source is unbound.
I have Me.cboSubcategory.Requery as an afterupdate event.

[cboSubcategory]'s row source is -
SELECT tblSubcategory.subcategoryid, tblSubcategory.subcategory FROM tblSubcategory WHERE tblSubcategory.Categoryid=Forms!Component!cboCateg ory ORDER BY tblSubcategory.Subcategory;

Control source is bound to SubcategoryID in tblComponent.

I have set up [tblCategory] as the one side of a one to many relationship with [tblSubcategory] and [tblSubcategory] as the one side of a one to many relationship with [tblComponent]. [SubcategoryID] (foreign key) is the only piece of 'category' information I am storing in [tblComponent]. I presume that's the correct thing to do since you can calculate the category from the stored subcategoryID.

The problem is that the form only seems to remember the most recent combo choice so if i fill in one record, navigate to another use the combos again, then navigate back, the original combo choice has been overwritten in the form record (although the underlying tblComponent seems to have the correct data written to it). In other words ALL records on my form display the last values that were entered using the combo boxes and not the correct values. Is this normal? I hope not, and if not then what am I doing wrong?

Thanks in advance :)