How to bring the he document to front while open.

Question

I have a problem. I used doc.Activate() to bring the document to front but it doesn't work, the document remains in back.

 

I am closing Blank active document firts.

if (app.ActiveDocument != null)
{
oWordDoc = app.ActiveDocument;
if (Ribbon1.docnum == 1)
{
oWordDoc.Close();
}

}
oWordDoc = app.Documents.Open(destinationPath, missing, false, missing, missing, missing, false, missing, missing, missing, missing, missing, missing
, missing, missing, missing);
app.Visible = true;
oWordDoc.Activate();

Please replay me fast. I am waiting.