diff --git a/app/controllers/student_work_controller.rb b/app/controllers/student_work_controller.rb
index 9006c8a79..661770206 100644
--- a/app/controllers/student_work_controller.rb
+++ b/app/controllers/student_work_controller.rb
@@ -1096,7 +1096,7 @@ class StudentWorkController < ApplicationController
       all_student_ids = "(" + pro.members.map{|member| member.user_id}.join(",") + ")"
     end
     all_students = User.where("id in #{all_student_ids}")
-    student_work_id = @homework.student_work_projects.where("user_id=?",User.current.id).empty? ? -1 : @homework.student_work_projects.where("user_id=?",User.current.id).first.student_work_id
+    student_work_id = @homework.student_work_projects.where("user_id=? and student_work_id is not null",User.current.id).first.nil? ? -1 : @homework.student_work_projects.where("user_id=?",User.current.id).first.student_work_id
     @commit_student_ids = @homework.student_work_projects.where("student_work_id != #{student_work_id}").map{|student| student.user_id}
     @users = searchstudent_by_name all_students,name
     respond_to do |format|
diff --git a/app/views/student_work/search_course_students.js.erb b/app/views/student_work/search_course_students.js.erb
index 2ac4eeaab..65179317f 100644
--- a/app/views/student_work/search_course_students.js.erb
+++ b/app/views/student_work/search_course_students.js.erb
@@ -8,19 +8,19 @@ $("#all_students_list").empty();
     $("#all_students_list").append(link);
 
     var str = $("#group_member_ids").val();
-    /*var str = "";
+    var choose_str = "";
     var lists = $("#choose_students_list li");
     if(lists.length > 0) {
         for(var i=0; i<lists.length; i++) {
             var id = $(lists[i]).attr("id").replace(/[^0-9]/ig,"");
-            str += id;
+            choose_str += id;
             if (i != lists.length -1) {
-                str += ",";
+                choose_str += ",";
         }
     }
-}*/
+}
     <% if user.id.to_i != User.current.id.to_i && (@commit_student_ids.find{|e| e.to_i == user.id.to_i}).nil? && user.member_of_course?(@course) %>
-        if (str.indexOf(<%=user.id.to_s %>) < 0) {
+        if (str.indexOf(<%=user.id.to_s %>) < 0 && choose_str.indexOf(<%=user.id.to_s %>) < 0) {
             $("#student_<%=user.id %>").one("click",function choose_student() {
                 var li = "<li id='choose_student_<%=user.id %>'";
                 <% if user.id.to_i != User.current.id.to_i %>