User form combo box
 

Hi,

I have a user form.

The first entry is a text box with a control source set to cell A1 on
my ws (so can be updated from form or ws)

The second entry is a combo box with a control source set to B1 on my
ws (so shows the cell b1 value when opened but can be changed by
selecting a different entry from the combo which then changes the
value in B1)

The third entry I would like to be linked to the second combo box. I
need it to be another combo box but I want to row source to be set
based on the value in the second combo box (or B1 as these will be the
same).

I guess this needs to be done programatically, but not sure when (ie.
it needs to be set on load of the form, and on change of the second
combo box).

Any help / suggestions would be great. Thanks,