I've had this problem in the past - what fixed it for me:

ThisForm.themes = .F.


>Hi,
>I have a real puzzler. Of the >230 forms (classes) in our application, one form sometimes comes up blank, no visible controls. Not always, just sometime. I can enter and save data, etc., because I know where to tab to, but the form is blank.
>
>I can get an obj ref to the form and its controls, read and set control values, etc., but it’s still blank.
>
>I’ve played with lockscreen, refresh(), SetFocus(), oForm.txtbox.visible = .t., change form size, whatever. The ShowWindow API call will minimize, maximize, whatever, but the form controls will not paint.
>
>If I close and re-instantiate the form it may open fine or it may be blank.
>
>Anyone ever run into this type of thing before?
>
>Thanks,
>
>Gary