Short version: change all form's to AutoScroll = False
The problem is the form's AutoScroll property, and how it affects which form size is stored in the DFM.
If AutoScroll is true (the default) the DFM will store Width and Height:
object Form1: TForm1
Left = 192
Top = 114
Width = 544
Height = 375
Caption = 'Form1'
...
If AutoScroll is false (the preferred setting) the DFM will store ClientWidth and ClientHeight:
object frmSplash: TfrmSplash
Left = 192
Top = 114
ClientWidth = 536
ClientHeight = 348
Caption = 'Form1'
The problem with storing Height is what happens when the user's caption bar is a different size than your development machine, e.g.
- you develop on Windows 2000, program runs on Windows XP
- you develop on Windows XP, program runs on Windows Vista
- you develop with small fonts, program runs with large fonts
Windows 2000 had a 4 pixel border, with a 23 pixel caption bar. With the DFM storing a Height of 375, this leaves 348px for form client area.
Run the same program on Windows XP, which has a taller (28 pixel) caption bar. With the DFM storing a Height of 375 pixels, this leaves 343px for client area.
Your form "got 5 pixels shorter".
You need to force Delphi to store the ClientWidth and ClientHeight in the DFM by turning AutoScroll off.
Now when you create your 348px tall form on Windows XP, it will continue to have 348 pixels in the client area - and be however extra tall is required to have a caption bar.
i go so far as to have an OutputDebugString and a breakpoint trigger if my helper library code finds any form that mistakenly has AutoScroll set to true.
Edit: Since i try to be a good developer, i make my form's respect the user's font preference. During the OnCreate of all my forms i call a StandardizeForm(Self) function that:
- scales the form to match the user's default font size
- changes the font on all controls on the form to the user's preference
- issues an ODS if the form is set mistakenly set to
Scaled
- issues an ODS and breakpoint if
AutoScroll true (and sets it to false)
- issues an ODS and breakpoint if
ShowHint is false (and turns it on)
- etc
You can do something similar. Yes you'd have to add:
procedure TCustomerEditForm.FormCreat(Sender: TObject);
begin
StandardizeForm(Self); //Pay your taxes!
...
end;
But it's worth it for me.