[#976] added optional RelationOptions.DisplayFields and refactored the relation picker UI

ui/src/scss/_alert.scss

@@ -105,6 +105,7 @@
     display: block;
     text-align: center;
     pointer-events: none;
+    transition: left var(--activeAnimationSpeed);
     .alert {
         text-align: left;
         pointer-events: auto;
@@ -112,10 +113,12 @@
         margin: var(--baseSpacing) auto;
         @include shadowize();
     }
-    .app-sidebar ~ .app-body & {
+}
+body:not(.overlay-active) {
+    .app-sidebar ~ .app-body .toasts-wrapper {
         left: var(--appSidebarWidth);
     }
-    .app-sidebar ~ .app-body .page-sidebar ~ & {
+    .app-sidebar ~ .app-body .page-sidebar ~ .toasts-wrapper {
         left: calc(var(--appSidebarWidth) + var(--pageSidebarWidth));
     }
 }