MOBILE-3068 ionic: Close modals before going back

src/app/app.component.ts

@@ -65,6 +65,19 @@ export class MoodleMobileApp implements OnInit {
                     app.setElementClass('platform-windows', true);
                 }
             }
+
+            // Register back button action to allow closing modals before anything else.
+            this.appProvider.registerBackButtonAction(() => {
+                // Following function is hidden in Ionic Code, however there's no solution for that.
+                const portal = app._getActivePortal();
+                if (portal) {
+                    portal.pop();
+
+                    return true;
+                }
+
+                return false;
+            }, 2000);
         });
 
     }

src/app/app.scss

@@ -1012,6 +1012,11 @@ ion-app.app-root {
   ion-alert .alert-checkbox-button .alert-checkbox-label {
     white-space: normal;
   }
+
+  ion-backdrop {
+    transition: opacity 100ms ease-in-out;
+    opacity: .1;
+  }
 }
 
 @each $color-name, $color-base, $color-contrast in get-colors($colors) {

src/components/context-menu/context-menu.ts

@@ -178,7 +178,7 @@ export class CoreContextMenuComponent implements OnInit, OnDestroy {
     showContextMenu(event: MouseEvent): void {
         if (!this.expanded) {
             const popover = this.popoverCtrl.create(CoreContextMenuPopoverComponent,
-                { title: this.title, items: this.items, id: this.uniqueId });
+                { title: this.title, items: this.items, id: this.uniqueId, showBackdrop: true });
 
             popover.onDidDismiss(() => {
                 this.expanded = false;