diff --git a/ui-ngx/src/app/core/interceptors/global-http-interceptor.ts b/ui-ngx/src/app/core/interceptors/global-http-interceptor.ts
index d008b8e5c7..69791908b3 100644
--- a/ui-ngx/src/app/core/interceptors/global-http-interceptor.ts
+++ b/ui-ngx/src/app/core/interceptors/global-http-interceptor.ts
@@ -129,10 +129,6 @@ export class GlobalHttpInterceptor implements HttpInterceptor {
           this.showError(req.method + ': ' + req.url + '<br/>' +
             errorResponse.status + ': ' + errorResponse.statusText);
         }
-      } else if (errorResponse.status === 504) {
-        if (!ignoreErrors) {
-          this.showError('Request timeout');
-        }
       } else {
         unhandled = true;
       }
diff --git a/ui-ngx/src/app/core/utils.ts b/ui-ngx/src/app/core/utils.ts
index bf57dd4441..7f13f08ba6 100644
--- a/ui-ngx/src/app/core/utils.ts
+++ b/ui-ngx/src/app/core/utils.ts
@@ -23,7 +23,7 @@ import { NULL_UUID } from '@shared/models/id/has-uuid';
 import { baseDetailsPageByEntityType, EntityType } from '@shared/models/entity-type.models';
 import { HttpClient, HttpErrorResponse } from '@angular/common/http';
 import { TranslateService } from '@ngx-translate/core';
-import { serverErrorCodesTranslations } from '@shared/models/constants';
+import { httpStatusMessageMap, serverErrorCodesTranslations } from '@shared/models/constants';
 import { SubscriptionEntityInfo } from '@core/api/widget-api.models';
 import {
   CompiledTbFunction,
@@ -910,11 +910,13 @@ export function parseHttpErrorMessage(errorResponse: HttpErrorResponse,
   } else {
     error = errorResponse.error;
   }
-  if (error && !error.message) {
-    errorMessage = prepareMessageFromData(error);
-  } else if (error && error.message) {
+  if (error && error.message) {
     errorMessage = error.message;
     timeout = error.timeout ? error.timeout : 0;
+  } else if (isProxyError(errorResponse)) {
+    errorMessage = httpStatusMessageMap.get(errorResponse.status);
+  } else if (error) {
+    errorMessage = prepareMessageFromData(error);
   } else {
     errorMessage = `Unhandled error code ${error ? error.status : '\'Unknown\''}`;
   }
@@ -951,6 +953,14 @@ function prepareMessageFromData(data): string {
   }
 }
 
+function isProxyError(errorResponse: HttpErrorResponse): boolean {
+  if (!httpStatusMessageMap.has(errorResponse.status)) {
+    return false;
+  }
+  const error = errorResponse.error;
+  return !error || typeof error === 'string' || (typeof error === 'object' && !error.message);
+}
+
 export const genNextLabel = (name: string, datasources: Datasource[]): string => {
   let label = name;
   let i = 1;
diff --git a/ui-ngx/src/app/shared/components/string-items-list.component.html b/ui-ngx/src/app/shared/components/string-items-list.component.html
index 106b79ab9a..7a0489345f 100644
--- a/ui-ngx/src/app/shared/components/string-items-list.component.html
+++ b/ui-ngx/src/app/shared/components/string-items-list.component.html
@@ -31,7 +31,6 @@
       <mat-icon matChipRemove *ngIf="!disabled">close</mat-icon>
     </mat-chip-row>
     <input matInput type="text"
-           (blur)="addOnBlur($event)"
            placeholder="{{ placeholder }}"
            style="max-width: 300px;min-width: 250px"
            #stringItemInput
@@ -40,20 +39,22 @@
            #origin="matAutocompleteOrigin"
            [matChipInputFor]="itemsChipList"
            [matChipInputSeparatorKeyCodes]="separatorKeysCodes"
+           [matChipInputAddOnBlur]="true"
            matAutocompleteOrigin
            (matChipInputTokenEnd)="addOnEnd($event)"
            [matAutocompleteConnectedTo]="origin"
            [matAutocomplete]="stringItemAutocomplete"
-           [matAutocompleteDisabled]="!predefinedValues?.length">
+           [matAutocompleteDisabled]="!predefinedValues?.length && !fetchOptionsFn">
   </mat-chip-grid>
   <mat-autocomplete #stringItemAutocomplete="matAutocomplete"
                     [displayWith]="displayValueFn"
+                    (optionSelected)="onOptionSelected($event)"
                     class="tb-autocomplete">
     @for (value of filteredValues | async; track value.value) {
-      <mat-option [value]="value"><span [innerHTML]="value.name | highlight:searchText"></span></mat-option>
+      <mat-option [value]="value" (mousedown)="$event.preventDefault()"><span [innerHTML]="value.name | highlight:searchText:true"></span></mat-option>
     } @empty {
       @if (!allowUserValue) {
-        <mat-option [value]="null">{{ 'common.not-found' | translate }}</mat-option>
+        <mat-option [value]="null" (mousedown)="$event.preventDefault()">{{ 'common.not-found' | translate }}</mat-option>
       }
     }
   </mat-autocomplete>
diff --git a/ui-ngx/src/app/shared/components/string-items-list.component.ts b/ui-ngx/src/app/shared/components/string-items-list.component.ts
index c7f905f68b..6d0c57ab0a 100644
--- a/ui-ngx/src/app/shared/components/string-items-list.component.ts
+++ b/ui-ngx/src/app/shared/components/string-items-list.component.ts
@@ -29,7 +29,7 @@ import { FloatLabelType, MatFormFieldAppearance, SubscriptSizing } from '@angula
 import { coerceArray, coerceBoolean } from '@shared/decorators/coercion';
 import { Observable, of } from 'rxjs';
 import { filter, mergeMap, share, tap } from 'rxjs/operators';
-import { MatAutocompleteTrigger } from '@angular/material/autocomplete';
+import { MatAutocompleteSelectedEvent, MatAutocompleteTrigger } from '@angular/material/autocomplete';
 import { isDefined, isUndefined } from '@core/utils';
 
 export interface StringItemsOption {
@@ -37,18 +37,18 @@ export interface StringItemsOption {
   value: any;
 }
 @Component({
-    selector: 'tb-string-items-list',
-    templateUrl: './string-items-list.component.html',
-    styleUrls: [],
-    providers: [
-        {
-            provide: NG_VALUE_ACCESSOR,
-            useExisting: forwardRef(() => StringItemsListComponent),
-            multi: true
-        }
-    ],
-    encapsulation: ViewEncapsulation.None,
-    standalone: false
+  selector: 'tb-string-items-list',
+  templateUrl: './string-items-list.component.html',
+  styleUrls: [],
+  providers: [
+    {
+      provide: NG_VALUE_ACCESSOR,
+      useExisting: forwardRef(() => StringItemsListComponent),
+      multi: true
+    }
+  ],
+  encapsulation: ViewEncapsulation.None,
+  standalone: false
 })
 export class StringItemsListComponent implements ControlValueAccessor, OnInit {
 
@@ -149,9 +149,7 @@ export class StringItemsListComponent implements ControlValueAccessor, OnInit {
       this.filteredValues = this.itemControl.valueChanges
         .pipe(
           tap((value) => {
-            if (value && typeof value !== 'string') {
-              this.add(value);
-            } else if (value === null) {
+            if (value === null) {
               this.clear();
             }
           }),
@@ -209,16 +207,17 @@ export class StringItemsListComponent implements ControlValueAccessor, OnInit {
     this.dirty = true;
   }
 
-  addOnBlur(event: FocusEvent) {
-    const target: HTMLElement = event.relatedTarget as HTMLElement;
-    if ((target && target.tagName !== 'MAT-OPTION') || this.allowUserValue) {
-      this.addItem(this.stringItemInput.nativeElement.value ?? '');
+  onOptionSelected(event: MatAutocompleteSelectedEvent): void {
+    if (event.option.value != null) {
+      this.add(event.option.value);
+    } else {
+      this.clear();
     }
-    this.onTouched();
   }
 
   addOnEnd(event: MatChipInputEvent): void {
-    this.addItem(event.value ?? '')
+    this.addItem(event.value ?? '');
+    this.onTouched();
   }
 
   removeItems(item: StringItemsOption) {
@@ -295,6 +294,8 @@ export class StringItemsListComponent implements ControlValueAccessor, OnInit {
     this.stringItemInput.nativeElement.value = value;
     this.itemControl.patchValue(value, {emitEvent: true});
     setTimeout(() => {
+      this.stringItemInput.nativeElement.value = value;
+      this.itemControl.patchValue(null, {emitEvent: false});
       this.stringItemInput.nativeElement.blur();
       this.stringItemInput.nativeElement.focus();
     }, 0);
diff --git a/ui-ngx/src/app/shared/models/constants.ts b/ui-ngx/src/app/shared/models/constants.ts
index 2890b4827c..afc68fdfcd 100644
--- a/ui-ngx/src/app/shared/models/constants.ts
+++ b/ui-ngx/src/app/shared/models/constants.ts
@@ -56,6 +56,12 @@ export const serverErrorCodesTranslations = new Map<number, string>([
   [Constants.serverErrorCode.entitiesLimitExceeded, 'server-error.entities-limit-exceeded'],
 ]);
 
+export const httpStatusMessageMap = new Map<number, string>([
+  [502, 'Server is temporarily unavailable (Bad Gateway)'],
+  [503, 'Server is temporarily unavailable'],
+  [504, 'Server did not respond in time (Gateway Timeout)'],
+]);
+
 export const MediaBreakpoints = {
   xs: 'screen and (max-width: 599px)',
   sm: 'screen and (min-width: 600px) and (max-width: 959px)',
diff --git a/ui-ngx/yarn.lock b/ui-ngx/yarn.lock
index 721b8b8006..8aafb1a243 100644
--- a/ui-ngx/yarn.lock
+++ b/ui-ngx/yarn.lock
@@ -6033,9 +6033,9 @@ flat@^5.0.2:
   integrity sha512-b6suED+5/3rTpUBdG1gupIl8MPFCAMA0QXwmljLhvCUKcUvdE4gWky9zpuGCcXHOsz4J9wPGNWq6OKpmIzz3hQ==
 
 flatted@^3.2.9:
-  version "3.4.1"
-  resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.4.1.tgz#84ccd9579e76e9cc0d246c11d8be0beb019143e6"
-  integrity sha512-IxfVbRFVlV8V/yRaGzk0UVIcsKKHMSfYw66T/u4nTwlWteQePsxe//LjudR1AMX4tZW3WFCh3Zqa/sjlqpbURQ==
+  version "3.4.2"
+  resolved "https://registry.yarnpkg.com/flatted/-/flatted-3.4.2.tgz#f5c23c107f0f37de8dbdf24f13722b3b98d52726"
+  integrity sha512-PjDse7RzhcPkIJwy5t7KPWQSZ9cAbzQXcafsetQoD7sOJRQlGikNbx7yZp2OotDnJyrDcbyRq3Ttb18iYOqkxA==
 
 "flot.curvedlines@https://github.com/MichaelZinsmaier/CurvedLines.git#master":
   version "1.1.1"