Delphi - How to prevent Forms/MsgBoxes to move under prior form?

Question

Many times after the Windows 98 era we have experienced that some dialogs lose their Z-Order and move back to the prior form.

For example:

Dialog1.Sh         


        

Answer 1

A trick I've used recently was to apply these two lines of code during the creation of each form:

SetWindowLong(Handle, GWL_EXSTYLE, GetWindowLong(Handle, GWL_EXSTYLE) or 
  WS_EX_APPWINDOW or WS_EX_TOPMOST);
SetWindowLong(Handle, GWL_HWNDPARENT, GetDesktopWindow);

Handle is the handle of the form (Form1.Handle). The WS_EX_APPWINDOW part makes each window appear on the task bar, remove it if you don't want that additional effect.

For my main form I use this line:

SetWindowLong(Handle, GWL_EXSTYLE, GetWindowLong(Handle, GWL_EXSTYLE) or
  WS_EX_TOPMOST);

I also use this function to help build my custom dialogs (I created a new function for each style of dialog - error, confirmation, etc.):

function CustomDlg(const AMessage : string; const ADlgType: TMsgDlgType;
  const AButtons: TMsgDlgButtons; const ADefaultButton: TMsgDlgBtn) : TForm;
begin
  Result := CreateMessageDialog(AMessage, ADlgType, AButtons, ADefaultButton);
  with Result do
    begin
      SetWindowLong(Handle, GWL_EXSTYLE, GetWindowLong(Handle, GWL_EXSTYLE) or 
        WS_EX_APPWINDOW or WS_EX_TOPMOST);
      SetWindowLong(Handle, GWL_HWNDPARENT, GetDesktopwindow);
      FormStyle := fsStayOnTop;
      BringToFront;
    end;
end;

The FormStyle := fsStayOnTop; part is optional, of course, but I use it to make sure my confirmation and error dialogs are always visible to the user.

It seems like a bit of work but the net effect is that I no longer have to worry about forms accidentally hiding behind other forms.