override PdfViewer event just for one form

[mazluta]

there is PDFViewer in 

FmSoft\uniGUI\uni-1.90.0.1551\pdf.js

there in viewer.js there is function 

function noContextMenuHandler(evt) {
  evt.preventDefault();
}

can i override this function just on my VIEWER form to change to

function noContextMenuHandler(evt) {
  evt.stopPropagation();
}

by some inner code in FormCreate, Active Or After PdfLoaded ?