>>What is the Style property set to?
>
>The button's style property is set to zero.

Is that after the form is instantiated? IOW, do you perhaps change this setting while the form is running?

If not, then you might add a straight, of-the-shelf button to form and incrementally adapt the problem buttons' settings and code to the new one til you discover what's different.

Updated: What is specialEffect set to?