This code working just fine in 10.3 Android & Windows ... dont' know with Tmodalresult
TDialogService.MessageDialog((mymessage),
system.UITypes.TMsgDlgType.mtConfirmation,
[system.UITypes.TMsgDlgBtn.mbYes, system.UITypes.TMsgDlgBtn.mbNo], system.UITypes.TMsgDlgBtn.mbYes,0,
procedure (const AResult: System.UITypes.TModalResult)
begin
case AResult of
mrYES: Begin .....
br,