diff --git a/ui-ngx/src/app/modules/home/components/alarm/alarm-table-config.ts b/ui-ngx/src/app/modules/home/components/alarm/alarm-table-config.ts
index 15e3fb1952..865a1b8c8b 100644
--- a/ui-ngx/src/app/modules/home/components/alarm/alarm-table-config.ts
+++ b/ui-ngx/src/app/modules/home/components/alarm/alarm-table-config.ts
@@ -319,9 +319,7 @@ export class AlarmTableConfig extends EntityTableConfig<AlarmInfo, TimePageLink>
     if ($event) {
       $event.stopPropagation();
     }
-    const unacknowledgedAlarms = alarms.filter(alarm => {
-      return alarm.status === AlarmStatus.CLEARED_UNACK || alarm.status === AlarmStatus.ACTIVE_UNACK;
-    })
+    const unacknowledgedAlarms = alarms.filter(alarm => !alarm.acknowledged);
     let title = '';
     let content = '';
     if (!unacknowledgedAlarms.length) {
@@ -356,9 +354,7 @@ export class AlarmTableConfig extends EntityTableConfig<AlarmInfo, TimePageLink>
     if ($event) {
       $event.stopPropagation();
     }
-    const activeAlarms = alarms.filter(alarm => {
-      return alarm.status === AlarmStatus.ACTIVE_ACK || alarm.status === AlarmStatus.ACTIVE_UNACK;
-    })
+    const activeAlarms = alarms.filter(alarm => !alarm.cleared);
     let title = '';
     let content = '';
     if (!activeAlarms.length) {
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/alarm/alarms-table-widget.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/alarm/alarms-table-widget.component.ts
index b6129b74a7..20f123972a 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/alarm/alarms-table-widget.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/alarm/alarms-table-widget.component.ts
@@ -896,12 +896,21 @@ export class AlarmsTableWidgetComponent extends PageComponent implements OnInit,
       $event.stopPropagation();
     }
     if (this.alarmsDatasource.selection.hasValue()) {
-      const alarmIds = this.alarmsDatasource.selection.selected.filter(
-        (alarmId) => alarmId !== NULL_UUID
+      const unacknowledgedAlarms = this.alarmsDatasource.selection.selected.filter(
+        alarm => alarm.id.id !== NULL_UUID && !alarm.acknowledged
       );
-      if (alarmIds.length) {
-        const title = this.translate.instant('alarm.aknowledge-alarms-title', {count: alarmIds.length});
-        const content = this.translate.instant('alarm.aknowledge-alarms-text', {count: alarmIds.length});
+      let title = '';
+      let content = '';
+      if (!unacknowledgedAlarms.length) {
+        title = this.translate.instant('alarm.selected-alarms', {count: unacknowledgedAlarms.length});
+        content = this.translate.instant('alarm.selected-alarms-are-acknowledged');
+        this.dialogService.alert(
+          title,
+          content
+        ).subscribe();
+      } else {
+        title = this.translate.instant('alarm.aknowledge-alarms-title', {count: unacknowledgedAlarms.length});
+        content = this.translate.instant('alarm.aknowledge-alarms-text', {count: unacknowledgedAlarms.length});
         this.dialogService.confirm(
           title,
           content,
@@ -909,16 +918,14 @@ export class AlarmsTableWidgetComponent extends PageComponent implements OnInit,
           this.translate.instant('action.yes')
         ).subscribe((res) => {
           if (res) {
-            if (res) {
-              const tasks: Observable<AlarmInfo>[] = [];
-              for (const alarmId of alarmIds) {
-                tasks.push(this.alarmService.ackAlarm(alarmId));
-              }
-              forkJoin(tasks).subscribe(() => {
-                this.alarmsDatasource.clearSelection();
-                this.subscription.update();
-              });
+            const tasks: Observable<AlarmInfo>[] = [];
+            for (const alarm of unacknowledgedAlarms) {
+              tasks.push(this.alarmService.ackAlarm(alarm.id.id));
             }
+            forkJoin(tasks).subscribe(() => {
+              this.alarmsDatasource.clearSelection();
+              this.subscription.update();
+            });
           }
         });
       }
@@ -952,12 +959,21 @@ export class AlarmsTableWidgetComponent extends PageComponent implements OnInit,
       $event.stopPropagation();
     }
     if (this.alarmsDatasource.selection.hasValue()) {
-      const alarmIds = this.alarmsDatasource.selection.selected.filter(
-        (alarmId) => alarmId !== NULL_UUID
+      const activeAlarms = this.alarmsDatasource.selection.selected.filter(
+        alarm => alarm.id.id !== NULL_UUID && !alarm.cleared
       );
-      if (alarmIds.length) {
-        const title = this.translate.instant('alarm.clear-alarms-title', {count: alarmIds.length});
-        const content = this.translate.instant('alarm.clear-alarms-text', {count: alarmIds.length});
+      let title = '';
+      let content = '';
+      if (!activeAlarms.length) {
+        title = this.translate.instant('alarm.selected-alarms', {count: activeAlarms.length});
+        content = this.translate.instant('alarm.selected-alarms-are-cleared');
+        this.dialogService.alert(
+          title,
+          content
+        ).subscribe();
+      } else {
+        title = this.translate.instant('alarm.clear-alarms-title', {count: activeAlarms.length});
+        content = this.translate.instant('alarm.clear-alarms-text', {count: activeAlarms.length});
         this.dialogService.confirm(
           title,
           content,
@@ -965,16 +981,14 @@ export class AlarmsTableWidgetComponent extends PageComponent implements OnInit,
           this.translate.instant('action.yes')
         ).subscribe((res) => {
           if (res) {
-            if (res) {
-              const tasks: Observable<AlarmInfo>[] = [];
-              for (const alarmId of alarmIds) {
-                tasks.push(this.alarmService.clearAlarm(alarmId));
-              }
-              forkJoin(tasks).subscribe(() => {
-                this.alarmsDatasource.clearSelection();
-                this.subscription.update();
-              });
+            const tasks: Observable<AlarmInfo>[] = [];
+            for (const alarm of activeAlarms) {
+              tasks.push(this.alarmService.clearAlarm(alarm.id.id));
             }
+            forkJoin(tasks).subscribe(() => {
+              this.alarmsDatasource.clearSelection();
+              this.subscription.update();
+            });
           }
         });
       }
@@ -1132,7 +1146,8 @@ class AlarmsDatasource implements DataSource<AlarmDataInfo> {
   private alarmsSubject = new BehaviorSubject<AlarmDataInfo[]>([]);
   private pageDataSubject = new BehaviorSubject<PageData<AlarmDataInfo>>(emptyPageData<AlarmDataInfo>());
 
-  public selection = new SelectionModel<string>(true, [], false);
+  public selection = new SelectionModel<AlarmDataInfo>(true, [], false,
+    (alarm1: AlarmDataInfo, alarm2: AlarmDataInfo) => alarm1.id.id === alarm2.id.id);
 
   private selectionModeChanged = new EventEmitter<boolean>();
 
@@ -1210,7 +1225,7 @@ class AlarmsDatasource implements DataSource<AlarmDataInfo> {
     }
     if (this.selection.hasValue()) {
       const alarmIds = alarms.map((alarm) => alarm.id.id);
-      const toRemove = this.selection.selected.filter(alarmId => alarmIds.indexOf(alarmId) === -1);
+      const toRemove = this.selection.selected.filter(alarm => alarmIds.indexOf(alarm.id.id) === -1);
       this.selection.deselect(...toRemove);
       if (this.selection.isEmpty()) {
         isEmptySelection = true;
@@ -1284,14 +1299,14 @@ class AlarmsDatasource implements DataSource<AlarmDataInfo> {
 
   toggleSelection(alarm: AlarmDataInfo) {
     const hasValue = this.selection.hasValue();
-    this.selection.toggle(alarm.id.id);
+    this.selection.toggle(alarm);
     if (hasValue !== this.selection.hasValue()) {
       this.onSelectionModeChanged(this.selection.hasValue());
     }
   }
 
   isSelected(alarm: AlarmDataInfo): boolean {
-    return this.selection.isSelected(alarm.id.id);
+    return this.selection.isSelected(alarm);
   }
 
   clearSelection() {
@@ -1312,7 +1327,7 @@ class AlarmsDatasource implements DataSource<AlarmDataInfo> {
           }
         } else {
           alarms.forEach(row => {
-            this.selection.select(row.id.id);
+            this.selection.select(row);
           });
           if (numSelected === 0) {
             this.onSelectionModeChanged(true);
diff --git a/ui-ngx/src/app/shared/models/alarm.models.ts b/ui-ngx/src/app/shared/models/alarm.models.ts
index 49f780beeb..71d64f2df1 100644
--- a/ui-ngx/src/app/shared/models/alarm.models.ts
+++ b/ui-ngx/src/app/shared/models/alarm.models.ts
@@ -102,6 +102,8 @@ export interface Alarm extends BaseData<AlarmId> {
   originator: EntityId;
   severity: AlarmSeverity;
   status: AlarmStatus;
+  acknowledged: boolean;
+  cleared: boolean;
   startTs: number;
   endTs: number;
   ackTs: number;
@@ -181,6 +183,8 @@ export const simulatedAlarm: AlarmInfo = {
   type: 'TEMPERATURE',
   severity: AlarmSeverity.MAJOR,
   status: AlarmStatus.ACTIVE_UNACK,
+  acknowledged: false,
+  cleared: false,
   details: {
     message: 'Temperature is high!'
   },