Bug #294094 --> follow up cleanup to the new filter action ui

Make pre-fill filters work again.
Make sure the target folder can file messages when saving a filter

r=neil
sr=bienveu
a=me

mailnews/base/search/resources/content/FilterEditor.js

@@ -114,8 +114,6 @@ function filterEditorOnLoad()
         filterAction.type = (getScopeFromFilterList(gFilterList) == Components.interfaces.nsMsgSearchScope.newsFilter) ? nsMsgFilterAction.Delete : nsMsgFilterAction.MoveToFolder;
         gFilter.appendAction(filterAction);
         initializeDialog(gFilter);
-        // Clear the default action added above now that the dialog is initialized.
-        gFilter.clearActionList();
       }
       else
       {
@@ -321,10 +319,9 @@ function saveFilter()
       gFilter.enabled=true;
     }
     else 
-    {
       isNewFilter = false;
-      gFilter.clearActionList();
-    }
+    
+    gFilter.clearActionList();
   }
 
   // add each filteraction to the filter

mailnews/base/search/resources/content/searchWidgets.xml

@@ -279,7 +279,8 @@
             {
               case "movemessage":
               case "copymessage":
-                if (!actionTarget.uri || actionTarget.uri == "") 
+                var msgFolder = actionTarget.uri ? GetMsgFolderFromUri(actionTarget.uri) : null;
+                if (!msgFolder || !msgFolder.canFileMessages) 
                   errorString = "mustSelectFolder";
                 break;
               case "forwardmessage":