diff --git a/src/scenario/scenario-store.js b/src/scenario/scenario-store.js
index 1f08ffb..9cfc16b 100644
--- a/src/scenario/scenario-store.js
+++ b/src/scenario/scenario-store.js
@@ -25,14 +25,59 @@ class ScenarioStore extends ArrayStore{
     super('scenarios', ScenariosDataManager);
   }
 
+  // calls to VILLASweb backend
   getUsers(token, id) {
     ScenariosDataManager.getUsers(token, id);
   }
 
+  addUser(token, id, username) {
+    ScenariosDataManager.addUser(token, id, username);
+  }
+
   deleteUser(token, id, username) {
     ScenariosDataManager.deleteUser(token, id, username);
   }
 
+  /* store functions, called when calls to backend have returned */
+  // save users after they are loaded ('getUsers' call)
+  saveUsers(state, action) {
+    let scenarioID = action.scenarioID;
+    state.forEach((element, index, array) => {
+      if (element.id === scenarioID) {
+        array[index]["users"] = action.users;
+        this.__emitChange();
+        return state;
+      }
+    })
+  }
+
+  // save new user after it was added to scenario ('addUser' call)
+  saveUser(state, action) {
+    let scenarioID = action.scenarioID;
+    state.forEach((element, index, array) => {
+      if (element.id === scenarioID) {
+        array[index]["users"].push(action.user);
+        this.__emitChange();
+        return state;
+      }
+    })
+  }
+
+  // remove user from ScenarioStore
+  removeUser(state, action) {
+    let scenarioID = action.scenarioID;
+    state.forEach((element, index, array) => {
+      if (element.id === scenarioID) {
+        const userindex = array[index]["users"].indexOf(action.user);
+        if (index > -1) {
+          array[index]["users"].splice(userindex, 1);
+        }
+        this.__emitChange();
+        return state;
+      }
+    })
+  }
+
   reduce(state, action) {
     switch (action.type) {
 
@@ -66,7 +111,14 @@ class ScenarioStore extends ArrayStore{
           return super.reduce(state, action);
         }
 
-//      case 'scenarios/users/start-load':
+      case 'scenarios/users':
+        return this.saveUsers(state, action);
+
+      case 'scenarios/user-added':
+        return this.saveUser(state, action);
+
+      case 'scenarios/user-deleted':
+        return this.removeUser(state, action);
 
       default:
         return super.reduce(state, action);
diff --git a/src/scenario/scenario.js b/src/scenario/scenario.js
index 2828767..706b0c2 100644
--- a/src/scenario/scenario.js
+++ b/src/scenario/scenario.js
@@ -56,6 +56,7 @@ class Scenario extends React.Component {
     // get selected scenario
     const sessionToken = LoginStore.getState().token;
     
+    let users = null;
     const scenario = ScenarioStore.getState().find(s => s.id === parseInt(props.match.params.scenario, 10));
     if (scenario == null) {
       AppDispatcher.dispatch({
@@ -64,8 +65,10 @@ class Scenario extends React.Component {
         token: sessionToken
       });
     }
+    else {
+      users = scenario.users;
+    }
     
-    let users = LoginStore.getState().scenarioUsers;
     let allUsers = UsersStore.getState();
     let allUserNames = [];
     allUsers.forEach((user) => {
@@ -114,6 +117,7 @@ class Scenario extends React.Component {
 
       addUserModal: false,
       deleteUserName: '',
+      deleteUserModal: false,
     }
   }
 
@@ -141,11 +145,13 @@ class Scenario extends React.Component {
   }
 
   // add User to Scenario
-  addUser() {
-
+  addUser(userindex) {
+    let username = this.state.allUserNames[userindex];
+    ScenarioStore.addUser(this.state.sessionToken, this.state.scenario.id, username);
   }
 
   closeDeleteUserModal() {
+    this.setState({deleteUserModal: false});
     ScenarioStore.deleteUser(this.state.sessionToken, this.state.scenario.id, this.state.deleteUserName);
   }
 
@@ -462,8 +468,7 @@ class Scenario extends React.Component {
       <div style={{ float: 'right' }}>
         <DropdownButton
           title="Add User"
-          onSelect={() => this.addUser()} 
-        //  style={buttonStyle}><Icon icon="plus" /> User
+          onSelect={(index) => this.addUser(index)} 
         >
           {this.state.allUserNames.map((opt,i) => (
             <Dropdown.Item key={i} eventKey={i}>
diff --git a/src/scenario/scenarios-data-manager.js b/src/scenario/scenarios-data-manager.js
index 9854901..bfa3422 100644
--- a/src/scenario/scenarios-data-manager.js
+++ b/src/scenario/scenarios-data-manager.js
@@ -24,14 +24,31 @@ class ScenariosDataManager extends RestDataManager {
   constructor() {
     super('scenario', '/scenarios');
 
-    this.onLoad =  this.onScenariosLoad
+    this.onLoad = this.onScenariosLoad
   }
 
   getUsers(token, id) {
     RestAPI.get(this.makeURL('/scenarios/' + id + '/users/'), token).then(response => {
       AppDispatcher.dispatch({
         type: 'scenarios/users',
-        users: response.users
+        users: response.users,
+        scenarioID: id
+      });
+    }).catch(error => {
+      AppDispatcher.dispatch({
+        type: 'scenarios/users-error',
+        error: error
+      })
+    })
+  }
+
+  addUser(token, id, username) {
+    let path = id + '/user';
+    RestAPI.put(this.requestURL('load/add', path, '?username=' + username), null, token).then(response => {
+      AppDispatcher.dispatch({
+        type: 'scenarios/user-added',
+        user: response.user,
+        scenarioID: id
       });
     }).catch(error => {
       AppDispatcher.dispatch({
@@ -42,19 +59,28 @@ class ScenariosDataManager extends RestDataManager {
   }
 
   deleteUser(token, id, username) {
-    RestAPI.delete(this.requestURL('remove/update', 'user', 'username='+username), token).then(response => {
-
+    let path = id + '/user';
+    RestAPI.delete(this.makeURL(this.url + '/' + path + '?username=' + username), token).then(response => {
+      AppDispatcher.dispatch({
+        type: 'scenarios/user-deleted',
+        user: response.user,
+        scenarioID: id
+      });
+    }).catch(error => {
+      AppDispatcher.dispatch({
+        type: 'scenarios/users-error',
+        error: error
+      })
     })
-    //super.remove(user, token, "scenarioID="+id);
   }
 
-  onScenariosLoad(data, token){
+  onScenariosLoad(data, token) {
 
     if (!Array.isArray(data)) {
       data = [data];
     }
 
-    for (let scenario of data){
+    for (let scenario of data) {
       AppDispatcher.dispatch({
         type: 'configs/start-load',
         token: token,
@@ -70,7 +96,7 @@ class ScenariosDataManager extends RestDataManager {
       AppDispatcher.dispatch({
         type: 'files/start-load',
         token: token,
-        param: '?scenarioID='+scenario.id,
+        param: '?scenarioID=' + scenario.id,
       });
     }
   }