Suspected BUG during design time?

Has anyone else noticed the following?

I've specified a form to have a border style of BSDialog,  hence it
appears during run time as a dialog box.

However,  when I go back into the design,  if the form is above a
certain size,  only part of the form appears - it has effectively been
'cut'.  I can still access the 'cut-off' components through the object
inspector though.  When I re-run the application the form appears as
normal again!

How about this - I re-specify the border style to be normal again,  
save the form, exit and re-enter Delphi, then when I bring the form up
at design stage it is there in all its glory.

What is going on?  Am I doing anything wrong?  Are dialogs limited to a
certain size?

Please Help......Anyone?

Thanks In Advance,

Dan