Solution:
The System modal dialog style (DS_SYSMODAL) was dropped as it is no longer supported in Win32. According to MSDN documentation:
This style is obsolete and is included for compatibility with 16-bit versions of Windows. If you specify this style, the system creates the dialog box with the WS_EX_TOPMOST style. This style does not prevent the user from accessing other windows on the desktop. Do not combine this style with the DS_CONTROL style.
You can still make a window top-most by using the following USER32.DLL function, in the Form OnLoad event:
SetWindowPos(Form.hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE)
Where the parameters are prototype as follows:
DLL User32
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File = User32.dll
DLL Types
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DLL Procedures
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Procedure SetWindowPos(hwnd, hwndInsertAfter, x, y, cx, cy, uFlags): Bool
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hwnd: Val AHandle
hwndInsertAfter: Val AHandle
x: Val Long
y: Val Long
cx: Val Long
cy: Val Long
uFlags: Val DWord
DLL Constants
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HWND_TOPMOST: AHandle Const = -1
SWP_NOSIZE: Long Const = 1
SWP_NOMOVE: Long Const = 2
SWP_NOZORDER: Long Const = 4
Sample files are available: 
Q200054.zip