tocoloro - 2021-04-27

I have the following code, catching the FileDialogStartEvent and checking if it should be displayed or not under isServerBusy() condition.
However, i can't manage to avoid the File Upload to display:

Public boolean onFileDialogStartEvent(FileDialogStartEvent fileDialogStartEvent) {
                        if (isServerBusy()) {
                            return false;
                        }
                        return true;
                    }

when serverBusy()= true , the File Upload Dialog is still displayed , even when it is returning false .
What Am I missing here?
(Firefox 74.0 (64-bit) , Ubuntu 16)

Thanks