mvvm - ContextMenu too-wide WPF -

i have built contextmenu dynamically using mvvm. problem : content of menuitems in right side ==> wide contextmenu. have ideea problem? thanks

here code in xaml:

<treeview.contextmenu>             <contextmenu name="rightclickmenu" itemssource="{binding path=selecteditem.menuitemslist}">                 <contextmenu.itemtemplate >                     <datatemplate>                     <!-- <menuitem horizontalalignment="left" header="{binding name}" command="{binding command}" -->                         <stackpanel orientation="horizontal">                             <image source="{binding myicon}"  width="18" height="18" snapstodevicepixels="true" />                         <menuitem  header="{binding name}" command="{binding command}"                                commandparameter="{binding relativesource={relativesource findancestor,              ancestortype={x:type treeview}}, path=datacontext.selecteditem}"                                   />                             </stackpanel>                     </datatemplate>                 </contextmenu.itemtemplate>             </contextmenu>         </treeview.contextmenu> 

it looks :

i want contextmenu this:

the second problem:

sometimes works these strange things.

------------------------------solved--------------------------------------------

for sac1. have modified solution adding x:shared="false". check msdn x:shared.

     <style targettype="menuitem" x:shared="false">                  <setter property="icon">                     <setter.value>                         <image source="{binding path=myicon}" height="20" width="20"  >                         </image>                     </setter.value>                 </setter>                 <setter property="header" value="{binding path=name}"  />                 <setter property="command" value="{binding command}" />                 <setter property="commandparameter" value="{binding relativesource={relativesource findancestor,                  ancestortype={x:type treeview}}, path=datacontext.selecteditem}" />             </style>    

for wrong headers of menu items had override method tostring() in menuitemviewmodel. don't undestand why had override tostring() works now.

public class menuitemviewmodel : bindablebase { ......  public string name     {                 {             return model.name;         }         set         {             this.model.name = value;             onpropertychanged("name");         }     }   public override string tostring()     {         return name;     }    ....   } 

datatemplate of menuitem not working expected. used style insted of datatemplate:

<treeview.resources>     <style targettype="menuitem">         <setter property="icon" value="{binding myicon}" />         <setter property="header" value="{binding name}" />         <setter property="command" value="{binding command}" />         <setter property="commandparameter" value="{binding relativesource={relativesource findancestor,          ancestortype={x:type treeview}}, path=datacontext.selecteditem}" />     </style> </treeview.resources> <treeview.contextmenu>     <contextmenu itemssource="{binding path=selecteditem.menuitemslist}" /> </treeview.contextmenu>