Why does .get_title() called from an (SPOnline) App-Web return an incorrect Localized DisplayName?

Can someone please explain me where I go wrong with the testcode (all the way the bottom)

I develop ViewMaster365.com Apps [using Microsoft Napa! so I can not do anything with .Net code] which Create Calculated Columns in the Host-Web; so in the Formulas I need to use Localized DisplayNames on non-english sites.

MSDN documentation for Field.get_title() says: Gets or sets value that specifies the display name of the field.

But On the same non-english Subsite get_title() returns different results when run directly in the site compared to when run from an App.

Steps to reproduce:

Run code in a teamsite

1. Create a non-english Locale subsite I used German in my example, its not my own language but can read it


2. Run the script below in Chrome Snippets

This produces the results I expect, get_title() gets me the localized DisplayName

Run code from an App-web

1. [install an (english¿) App with read rights in]


2. Now open the App in that same subsite (now Host-web)


3. Run the script below in Chrome Snippets the script is now accessing the subsite through the App-web

Now get_title() returns me the DisplayName as if the site was an English Locale;

!! extracting the DisplayName from the SchemaXml clearly shows the correct DisplayName !!

It looks to me like get_title() returns the Locale DisplayName of the App Web instead of the Host-Web.. (I have not tested what happens with an App which is not in english.. couldn't find one; and with Napa I can only create english Apps)

Test code

Code to be run as Chrome Snippets (or any way you want it)

try-catch is used to try App code first; if it fails it defaults to the current ClientContext

    var listName='Tasks';
    var reportDIV=document.getElementById('DeltaPlaceHolderMain');
    var listTitle='<h1>'+listName+'</h1>';
    reportDIV.innerHTML=listTitle;
    var context,web;
    JSRequest.EnsureSetup();
    try{
        context = new SP.ClientContext(decodeURIComponent(JSRequest.QueryString["SPAppWebUrl"]));
        var appContextSite = new SP.AppContextSite(context, decodeURIComponent(JSRequest.QueryString["SPHostUrl"]));
        web = appContextSite.get_web();
    } catch(e){
        context = new SP.ClientContext.get_current();
        web=context.get_web();    
    }
    listTitle+='<h2>context.get_url() = '+context.get_url()+'</h2>';
    var fields=web.get_lists().getByTitle( listName ).get_fields();
    context.load(fields);
    context.executeQueryAsync(
        function(){
            var fieldEnumerator = fields.getEnumerator();
            var rows=0,table='<tr><td><b>get_internalName()</b></td><td><b>get_title()</b></td><td><b>DisplayName from get_schemaXml()</b></td></tr>';
            while (fieldEnumerator.moveNext()) {
                var field=fieldEnumerator.get_current();
                var DisplayName = field.get_schemaXml().split('DisplayName="')[1].split('"')[0];
                var Title=field.get_title();
                Title = DisplayName!=Title ? '<b style="color:red">'+Title+'</b>' : Title;
                var cols = []; cols.push( field.get_internalName() , Title , DisplayName );
                table+='<tr style="background-color:#E0E7F'+(rows++%2?1:10)+'"><td>'+cols.join('</td><td>')+'</td></tr>';
            }
            reportDIV.innerHTML=listTitle+'<table width=100%>'+table+'</table>';
        }
    ,
        function( sender,args){ alert(args.get_message())}
    );