diff --git a/client/src/app/site/motions/modules/category/category-routing.module.ts b/client/src/app/site/motions/modules/category/category-routing.module.ts
index ad4198dee..7a7d3eb52 100644
--- a/client/src/app/site/motions/modules/category/category-routing.module.ts
+++ b/client/src/app/site/motions/modules/category/category-routing.module.ts
@@ -2,10 +2,11 @@ import { NgModule } from '@angular/core';
 import { Routes, RouterModule } from '@angular/router';
 import { CategoryListComponent } from './components/category-list/category-list.component';
 import { CategorySortComponent } from './components/category-sort/category-sort.component';
+import { WatchSortingTreeGuard } from 'app/shared/utils/watch-sorting-tree.guard';
 
 const routes: Routes = [
     { path: '', component: CategoryListComponent, pathMatch: 'full' },
-    { path: ':id', component: CategorySortComponent }
+    { path: ':id', component: CategorySortComponent, canDeactivate: [WatchSortingTreeGuard] }
 ];
 
 @NgModule({
diff --git a/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.html b/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.html
index 530ca80e4..7b8df5fc7 100644
--- a/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.html
+++ b/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.html
@@ -1,5 +1,9 @@
 <!-- TODO permission -->
-<os-head-bar [nav]="false">
+<os-head-bar
+    [editMode]="hasChanged"
+    (saveEvent)="sendUpdate()"
+    (mainEvent)="onCancel()"
+    [nav]="false">
     <!-- Title -->
     <div class="title-slot"><h2 translate>Sort motions</h2></div>
 </os-head-bar>
@@ -15,20 +19,26 @@
         mat-raised-button
         color="primary"
         (click)="onNumberMotions()"
-        class="spacer-top-10"
-        [disabled]="!motionsCount"
+        class="spacer-top-10 spacer-bottom-10"
+        [disabled]="!motionsCount || hasChanged"
     >
         <span translate>Number motions</span>
     </button>
-    <os-sorting-list [input]="motionObservable" #sorter>
+
+    <os-sorting-list
+        (sortEvent)="onListUpdate($event)"
+        [input]="motionObservable"
+        #sorter
+    >
         <!-- implicit motion references into the component using ng-template slot -->
         <ng-template let-motion>
-            <div class="ellipsis-overflow small" *ngIf="motion.tags && motion.tags.length">
+            <span class="ellipsis-overflow small" *ngIf="motion.tags && motion.tags.length">
                 <span *ngFor="let tag of motion.tags">
                     <mat-icon inline>local_offer</mat-icon>
                     {{ tag.getTitle() }}
                 </span>
-            </div>
+            </span>
+            <mat-chip matTooltip="{{ 'Sequential number' | translate }}">{{ motion.id }}</mat-chip>
         </ng-template>
     </os-sorting-list>
 </mat-card>
diff --git a/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.ts b/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.ts
index f7fb1dada..db45bcbcc 100644
--- a/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.ts
+++ b/client/src/app/site/motions/modules/category/components/category-sort/category-sort.component.ts
@@ -12,6 +12,7 @@ import { PromptService } from 'app/core/ui-services/prompt.service';
 import { SortingListComponent } from 'app/shared/components/sorting-list/sorting-list.component';
 import { ViewCategory } from 'app/site/motions/models/view-category';
 import { ViewMotion } from 'app/site/motions/models/view-motion';
+import { CanComponentDeactivate } from 'app/shared/utils/watch-sorting-tree.guard';
 
 /**
  * View for rearranging and renumbering the motions of a category. The {@link onNumberMotions}
@@ -23,7 +24,7 @@ import { ViewMotion } from 'app/site/motions/models/view-motion';
     templateUrl: './category-sort.component.html',
     styleUrls: ['./category-sort.component.scss']
 })
-export class CategorySortComponent extends BaseViewComponent implements OnInit {
+export class CategorySortComponent extends BaseViewComponent implements OnInit, CanComponentDeactivate {
     /**
      * The current category. Determined by the route
      */
@@ -39,6 +40,22 @@ export class CategorySortComponent extends BaseViewComponent implements OnInit {
      */
     public motionsCount = 0;
 
+    /**
+     * Flag to define if the list has changed.
+     */
+    public hasChanged = false;
+
+    /**
+     * Copied array of the motions in this category
+     */
+    private motionsCopy: ViewMotion[] = [];
+
+    /**
+     * Array that contains the initial list of motions.
+     * Necessary to reset the list.
+     */
+    private motionsBackup: ViewMotion[] = [];
+
     /**
      * @returns an observable for the {@link motionsSubject}
      */
@@ -95,11 +112,27 @@ export class CategorySortComponent extends BaseViewComponent implements OnInit {
         });
         this.motionRepo.getViewModelListObservable().subscribe(motions => {
             const filtered = motions.filter(m => m.category_id === category_id);
+            this.motionsBackup = [...filtered];
             this.motionsCount = filtered.length;
-            this.motionsSubject.next(filtered);
+            if (this.motionsCopy.length === 0) {
+                this.initializeList(filtered);
+            } else {
+                this.motionsSubject.next(this.handleMotionUpdates(filtered));
+            }
         });
     }
 
+    /**
+     * Function to (re-)set the current list of motions.
+     *
+     * @param motions An array containing the new motions.
+     */
+    private initializeList(motions: ViewMotion[]): void {
+        motions.sort((a, b) => (a.category_weight < b.category_weight ? -1 : 1));
+        this.motionsSubject.next(motions);
+        this.motionsCopy = motions;
+    }
+
     /**
      * Triggers a (re-)numbering of the motions after a configmarion dialog
      *
@@ -117,4 +150,86 @@ export class CategorySortComponent extends BaseViewComponent implements OnInit {
             }
         }
     }
+
+    /**
+     * Listener for the sorting event in the `sorting-list`.
+     *
+     * @param motions ViewMotion[]: The sorted array of motions.
+     */
+    public onListUpdate(motions: ViewMotion[]): void {
+        this.hasChanged = true;
+        this.motionsCopy = motions;
+    }
+
+    /**
+     * Resets the current list.
+     */
+    public async onCancel(): Promise<void> {
+        if (await this.canDeactivate()) {
+            this.motionsSubject.next([]);
+            this.initializeList(this.motionsBackup);
+            this.hasChanged = false;
+        }
+    }
+
+    /**
+     * This function sends the changed list.
+     * Only an array containing ids from the motions will be sent.
+     */
+    public async sendUpdate(): Promise<void> {
+        const title = this.translate.instant('Save changes');
+        const content = this.translate.instant('Do you really want to save your changes?');
+        if (await this.promptService.open(title, content)) {
+            const ids = this.motionsCopy.map(motion => motion.id);
+            this.repo.sortMotionsInCategory(this.category.category, ids);
+            this.hasChanged = false;
+        }
+    }
+
+    /**
+     * This function handles the incoming motions after the user sorted them previously.
+     *
+     * @param nextMotions are the motions that are received from the server.
+     *
+     * @returns An array containing the new motions or not the removed motions.
+     */
+    private handleMotionUpdates(nextMotions: ViewMotion[]): ViewMotion[] {
+        const copy = this.motionsCopy;
+        if (nextMotions.length > copy.length) {
+            for (const motion of nextMotions) {
+                if (!this.motionsCopy.includes(motion)) {
+                    copy.push(motion);
+                }
+            }
+        } else if (nextMotions.length < copy.length) {
+            for (const motion of copy) {
+                if (!nextMotions.includes(motion)) {
+                    copy.splice(copy.indexOf(motion), 1);
+                }
+            }
+        } else {
+            for (const motion of copy) {
+                if (!nextMotions.includes(motion)) {
+                    const updatedMotion = nextMotions.find(theMotion => theMotion.id === motion.id);
+                    copy.splice(copy.indexOf(motion), 1, updatedMotion);
+                }
+            }
+        }
+        return copy;
+    }
+
+    /**
+     * Function to open a prompt dialog,
+     * so the user will be warned if he has made changes and not saved them.
+     *
+     * @returns The result from the prompt dialog.
+     */
+    public async canDeactivate(): Promise<boolean> {
+        if (this.hasChanged) {
+            const title = this.translate.instant('You made changes.');
+            const content = this.translate.instant('Do you really want to exit?');
+            return await this.promptService.open(title, content);
+        }
+        return true;
+    }
 }