[Lazarus] patch for /rx/rxpopupunit.pas

[FreeMan]

/rx/rxpopupunit.pas
line:479
in
constructor TPopUpForm.CreatePopUp..........
......
{$ELSE}
   PopupOrigin:=TCustomControl(AOwner).ControlToScreen(Point(0, 
TCustomControl(AOwner).Height));
    FormStyle := fsStayOnTop;// added FreeMan
{$ENDIF}

why added:
TRxDBLookupCombo work good on osx (unix) system, but crosscompiled to 
win32 when open Popupform (grid's owner) quickly hide, and not show one 
more, because created, and get accec voilation.
I did formstyle to StayOnTop so work normally now for me.