Gets the tree reloading when the customtreeparams change too so now the language selection will auto trigger the tree to reload ... next task we'll make it re-sycn and work.

src/Umbraco.Web.UI.Client/src/common/directives/components/tree/umbtree.directive.js

@@ -420,8 +420,8 @@ function umbTreeDirective($compile, $log, $q, $rootScope, treeService, notificat
                     emitEvent("treeNodeAltSelect", { element: elem, tree: scope.tree, node: n, event: ev });
                 };
 
-                //watch for section changes
-                scope.$watch("section", function (newVal, oldVal) {
+                //watch for section changes and customtreeparams changes
+                scope.$watchCollection("[section, customtreeparams]", function (newVal, oldVal) {
 
                     if (!scope.tree) {
                         loadTree();
@@ -440,7 +440,7 @@ function umbTreeDirective($compile, $log, $q, $rootScope, treeService, notificat
                         //clear any active trees to reset lookups
                         lastSection = newVal;
                     }
-                });
+                });
 
                 setupExternalEvents();
                 loadTree();

src/Umbraco.Web.UI.Client/src/views/common/overlays/treepicker/treepicker.controller.js

@@ -170,7 +170,16 @@ angular.module("umbraco").controller("Umbraco.Overlays.TreePickerController",
                 queryParams["languageId"] = vm.selectedLanguage.id;
             }
             var queryString = $.param(queryParams); //create the query string from the params object
-            vm.customTreeParams = queryString + (queryString ? "&" : "") + ($scope.model.customTreeParams ? $scope.model.customTreeParams : "");
+            
+            if (!queryString) {
+                vm.customTreeParams = $scope.model.customTreeParams;
+            }
+            else {
+                vm.customTreeParams = queryString;
+                if ($scope.model.customTreeParams) {
+                    vm.customTreeParams += "&" + $scope.model.customTreeParams;
+                }
+            }
 
             vm.treeReady = true;
         }

src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js

@@ -135,7 +135,9 @@ function contentPickerController($scope, entityResource, editorState, iconHelper
         },
         treeAlias: $scope.model.config.startNode.type,
         section: $scope.model.config.startNode.type,
-        idType: "int"
+        idType: "int",
+        //only show the lang selector for content
+        showLanguageSelector: $scope.model.config.startNode.type === "content"
     };
 
     //since most of the pre-value config's are used in the dialog options (i.e. maxNumber, minNumber, etc...) we'll merge the