fix(modal): make sure modal container is the same as UIkit container

addon/components/uk-modal.js

@@ -5,6 +5,8 @@ import { guidFor } from "@ember/object/internals";
 import Component from "@glimmer/component";
 import { tracked } from "@glimmer/tracking";
 
+import container from "ember-uikit/container";
+
 function isBubbling(event) {
   return event.target !== event.currentTarget;
 }
@@ -27,7 +29,7 @@ export default class UkModal extends Component {
   get containerSelector() {
     // Only set the container to the default if no query string was passed as argument.
     if (typeof this.args.container !== "string") {
-      return getOwner(this).rootElement || "body";
+      return container.selector ?? "body";
     }
 
     return this.args.container;

addon/container.js

@@ -0,0 +1 @@
+export default { selector: null };

addon/instance-initializers/uikit.js

@@ -1,6 +1,8 @@
 import { getOwner } from "@ember/application";
 import UIkit from "uikit";
 
+import container from "ember-uikit/container";
+
 export function initialize(appInstance) {
   // As there is only a single `Router` across the whole app, which is owned
   // by the root `Application`, this reliably finds the root `Application`
@@ -9,6 +11,7 @@ export function initialize(appInstance) {
   const hostApp = getOwner(appInstance.lookup("router:main"));
 
   UIkit.container = hostApp.rootElement;
+  container.selector = hostApp.rootElement;
 }
 
 export default { initialize };