Eric,
You can use a builder to tweak your form at design time. If you've never done one there's a few examples over on my website. What you want here can be done with 4 lines of code. Realize though that you are changing the object properties and the form will save with the textboxes with the new SpecialEffect setting.
>I have sub-classed the textbox object. I would like to set it as specialeffect = flat or 3d depending on a public variable. It works fine when it runs but I would like to see it 3d or flat during the development (it is a setup for the current application). When I add the textbox on a form, when developping, I would like to see it flat or 3d depending on the public variable.