1024x768 video driver changes component size

Any body know why my buttons,bitmaps
and panels stay the same
size as designed in 640x480 and 800x600 mode
but expand in 1024x768 mode?
Eg: Designed in 640x480 and 800x600:

    speedbutton1.width = 25
    speedbutton1.height = 25

I fire up Delphi in 1024x768 and the button has grown to 31x31.
Delphi's own buttons and panels don't do this.
Do I need to pre-set all these components before showing the form?
I hope not.
I have D1 (still) and
Trident 512K video card.

Thanks up front,
Simon McCauley

PS. thanks for all the answers on my 'warnings' post.