Avoid that two banners are shown in case a wp is a child AND follows another wp. In that case only the warning should be shown.

frontend/src/app/shared/components/datepicker/banner/datepicker-banner.component.html

@@ -20,7 +20,7 @@
 </op-modal-banner>
 <ng-container *ngIf="!scheduleManually && !isParent">
   <op-modal-banner
-    *ngIf="(hasPrecedingRelations$ | async) === true && (hasFollowingRelations$ | async) === false"
+    *ngIf="(hasPrecedingRelations$ | async) === true && (hasFollowingRelations$ | async) === false && !isChild"
     type="info"
     [title]="text.start_date_limited_by_relations"
     [subtitle]="text.click_on_show_relations_to_open_gantt"