View property "InplaceSearchEnabled" in onet.xml ignored

i couldn't get the InplaceSearch displayed on my webpart through onet.xml.

in my onet.xml file:

<View List="Lists/Aufgaben" BaseViewID="1" WebPartZoneID="TaskTab">
      <![CDATA[
        <webParts> 
            <webPart xmlns="http://ift.tt/1fI5tWY"> 
                <metaData> 
                    <type name="Microsoft.SharePoint.WebPartPages.XsltListViewWebPart, Microsoft.SharePoint, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" /> 
                    <importErrorMessage>Cannot import this Web Part.</importErrorMessage>
                </metaData> 
                <data> 
                    <properties>
                      <property name="Title" type="string">Aufgaben</property>
                      <property name="ChromeType">None</property>
                      <property name="InplaceSearchEnabled">True</property>
                    </properties> 
                </data> 
            </webPart> 
        </webParts>   
        ]]>
    </View>

If I go on the page which is created with this onet.xml, there is the webpart shown but without the Inplace Search.

But... if I double check with PowerShell InplaceSearchEnabled property is correctly set to "True".

But... if I dribble check the WebPart properties on the page (over edit page...) the checkbox for InplaceSearch is not checked.

All other properties work fine (like Title and ChromeType). Why the InplaceSearch don't :(