> Im using precisely F4 to get the focus on the combo box

I'd keep the native behavior, but that's JMO. The way to set focus on controls is to have a label with an accelerator key and with the tabstop set to one before the control needing focus. Then, since labels don't get focus, the focus will be put on the control. This will be nicely accessible by sighted and visually impaired both.

Meant to add: you make an accelerator key by use "\<" before the letter. "\
> Now another question: is it possible to change the backcolor of a field in a grid depending on the value of that field? Not the whole column or row, but that single field.

You'll get better response if you post seperate question in seperate threads with a specific subject. For example: "How do I dynamically change one cell in a grid?"

I don't have a quick answer for it, I'm sorry, but it'll probably involve Sparse = .F.