How do I programatically add code to a header?

I use a local view to populate my grid and I would like to select which field
in the table to display in a column dynamically.  For example if field 1 is
null then display field 2 instead.  I'm only trying to evaluate the source
control between the two fields in the view.  I have ...

O my issue is that the Grid is not filtering records based off the value
selected in the Combo box.   It is returning all the records in the child
table rather then just the records for the record selected in the parent
table.  Has anyone ever encountered this?  I am sure.  What ...

OK I need Help!!!!  I can get this to work on a brand new form and I look at
the properties in the new for and compare them to my original form and they
look the same but I cannot get my original form to behave correctly.  Please
help!!!!!

I have two table
one is history
one is techcall
history is parent table while techcall is child

I have a Grid I am trying to link to a Grid so that every time the value of
the combo changes the grid changes accordingly.
Here is the code for setting up the combo box and the grid....what am I
doing wrong?  Because the grid is not updating when I change the value in

Despite not wanting any tooltips appearing when hovering over rows / columns
in my grid they still seem to appear when the underlying data is numeric /
currency.
I've tried setting the tooltiptext to NONE for the grid / column & text box