Hi we have done the small change in admin.js function and its working fine for us.
$(document).ready(function() {
$(".AppBar a").each(function(i, link) {
var href = $(link).attr("href");
if (href.indexOf("#newwindow") > 0) {
$(link).click(function(e){
$(link).attr("target","_blank");
href = href.substring(0,href.indexOf("#newwindow"));
$(link).attr("href",href);
});
}
});
})
and used the below in default.xml (navigation)
<a href="http://google.co.in#newWindow" target="_blank">Click Here</a>
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