c# - listview wrappanel not working when ungrouped -

i'm adapting solution needs: http://www.abhisheksur.com/2010/08/woring-with-icollectionviewsource-in.html

the xaml part of listview is:

    <listview grid.row="1" name="lvicons" itemssource="{binding}">         <listview.groupstyle>             <groupstyle>                 <groupstyle.headertemplate>                     <datatemplate>                         <textblock text="{binding name}" />                     </datatemplate>                 </groupstyle.headertemplate>             </groupstyle>         </listview.groupstyle>         <listview.itemspanel>             <itemspaneltemplate>                 <wrappanel width="{binding (frameworkelement.actualwidth),          relativesource={relativesource ancestortype=scrollcontentpresenter}}"         itemwidth="{binding (listview.view).itemwidth,          relativesource={relativesource ancestortype=listview}}"         minwidth="{binding itemwidth, relativesource={relativesource self}}"         itemheight="{binding (listview.view).itemheight,          relativesource={relativesource ancestortype=listview}}" />             </itemspaneltemplate>         </listview.itemspanel>      </listview> 

i've got button control if want show grouped or not , code behind button is:

private void btngroup_click(object sender, routedeventargs e)     {         this.source.groupdescriptions.clear();          propertyinfo pinfo = typeof(country_icon).getproperty(cmbgroups.text);         if (pinfo != null)             this.source.groupdescriptions.add(new ropertygroupdescription(pinfo.name));      } 

when grouping on, wrappanel working nicely (i'm grouping integer property on icons)

but when grouping not on, no wrapping:

i'm not worried different sizes of icon's - i'll fix later.

how fix wrapping when not grouped ? there different template in use ?

thanks answer of question wpf listview horizontal arrangement of items? me now.