diff --git a/src/core/components/horizontal-scroll-controls/core-horizontal-scroll-controls.html b/src/core/components/horizontal-scroll-controls/core-horizontal-scroll-controls.html
index b49f2c683..f23a2ee22 100644
--- a/src/core/components/horizontal-scroll-controls/core-horizontal-scroll-controls.html
+++ b/src/core/components/horizontal-scroll-controls/core-horizontal-scroll-controls.html
@@ -1,9 +1,9 @@
-<ion-button fill="clear" (click)="scroll('backward')" [hidden]="scrollPosition === 'hidden'" [disabled]="scrollPosition === 'start'"
+<ion-button fill="clear" (click)="scroll($event, 'backward')" [hidden]="scrollPosition === 'hidden'" [disabled]="scrollPosition === 'start'"
     [attr.aria-label]="'core.scrollbackward' | translate" [attr.aria-controls]="targetId">
     <ion-icon name="fas-chevron-left" slot="icon-only" aria-hidden="true" flip-rtl="false"></ion-icon>
 </ion-button>
 
-<ion-button fill="clear" (click)="scroll('forward')" [hidden]="scrollPosition === 'hidden'" [disabled]="scrollPosition === 'end'"
+<ion-button fill="clear" (click)="scroll($event, 'forward')" [hidden]="scrollPosition === 'hidden'" [disabled]="scrollPosition === 'end'"
     [attr.aria-label]="'core.scrollforward' | translate" [attr.aria-controls]="targetId">
     <ion-icon name="fas-chevron-right" slot="icon-only" aria-hidden="true" flip-rtl="false"></ion-icon>
 </ion-button>
diff --git a/src/core/components/horizontal-scroll-controls/horizontal-scroll-controls.ts b/src/core/components/horizontal-scroll-controls/horizontal-scroll-controls.ts
index 1842b0229..7541826af 100644
--- a/src/core/components/horizontal-scroll-controls/horizontal-scroll-controls.ts
+++ b/src/core/components/horizontal-scroll-controls/horizontal-scroll-controls.ts
@@ -44,13 +44,17 @@ export class CoreHorizontalScrollControlsComponent {
     /**
      * Scroll the target in the given direction.
      *
+     * @param ev Click event
      * @param direction Scroll direction.
      */
-    scroll(direction: 'forward' | 'backward'): void {
+    scroll(ev: Event, direction: 'forward' | 'backward'): void {
         if (!this.target) {
             return;
         }
 
+        ev.stopPropagation();
+        ev.preventDefault();
+
         const leftDelta = direction === 'forward' ? this.target.clientWidth : -this.target.clientWidth;
         const newScrollLeft = Math.max(
             Math.min(
diff --git a/src/core/features/courses/components/course-list-item/course-list-item.ts b/src/core/features/courses/components/course-list-item/course-list-item.ts
index c13587b47..56948e855 100644
--- a/src/core/features/courses/components/course-list-item/course-list-item.ts
+++ b/src/core/features/courses/components/course-list-item/course-list-item.ts
@@ -163,8 +163,6 @@ export class CoreCoursesCourseListItemComponent implements OnInit, OnDestroy, On
 
     /**
      * Open a course.
-     *
-     * @param course The course to open.
      */
     openCourse(): void {
         if (this.isEnrolled) {
@@ -179,6 +177,8 @@ export class CoreCoursesCourseListItemComponent implements OnInit, OnDestroy, On
 
     /**
      * Initialize prefetch course.
+     *
+     * @param forceInit Force initialization of prefetch course info.
      */
     async initPrefetchCourse(forceInit = false): Promise<void> {
         if (!this.isEnrolled || !this.showDownload ||
diff --git a/src/core/features/user/services/user.ts b/src/core/features/user/services/user.ts
index 0be9e9a8a..e54cdb230 100644
--- a/src/core/features/user/services/user.ts
+++ b/src/core/features/user/services/user.ts
@@ -137,11 +137,11 @@ export class CoreUserProvider {
 
         const result = await site.write<CoreUserUpdatePictureWSResponse>('core_user_update_picture', params);
 
-        if (!result.success) {
+        if (!result.success || !result.profileimageurl) {
             return Promise.reject(null);
         }
 
-        return result.profileimageurl!;
+        return result.profileimageurl;
     }
 
     /**
@@ -452,7 +452,7 @@ export class CoreUserProvider {
             name,
         };
         const preSets: CoreSiteWSPreSets = {
-            cacheKey: this.getUserPreferenceCacheKey(params.name!),
+            cacheKey: this.getUserPreferenceCacheKey(name),
             updateFrequency: CoreSite.FREQUENCY_SOMETIMES,
         };
 
@@ -613,7 +613,7 @@ export class CoreUserProvider {
         const treated: Record<string, boolean> = {};
 
         await Promise.all(userIds.map(async (userId) => {
-            if (userId === null) {
+            if (userId === null || !siteId) {
                 return;
             }
 
@@ -630,7 +630,7 @@ export class CoreUserProvider {
                 const profile = await this.getProfile(userId, courseId, false, siteId);
 
                 if (profile.profileimageurl) {
-                    await CoreFilepool.addToQueueByUrl(siteId!, profile.profileimageurl);
+                    await CoreFilepool.addToQueueByUrl(siteId, profile.profileimageurl);
                 }
             } catch (error) {
                 this.logger.warn(`Ignore error when prefetching user ${userId}`, error);
@@ -658,7 +658,7 @@ export class CoreUserProvider {
         const promises = entries.map(async (entry) => {
             const imageUrl = <string> entry[propertyName];
 
-            if (!imageUrl || treated[imageUrl]) {
+            if (!imageUrl || treated[imageUrl] || !siteId) {
                 // It doesn't have an image or it has already been treated.
                 return;
             }
@@ -666,7 +666,7 @@ export class CoreUserProvider {
             treated[imageUrl] = true;
 
             try {
-                await CoreFilepool.addToQueueByUrl(siteId!, imageUrl);
+                await CoreFilepool.addToQueueByUrl(siteId, imageUrl);
             } catch (ex) {
                 this.logger.warn(`Ignore error when prefetching user avatar ${imageUrl}`, entry, ex);
             }
@@ -682,7 +682,7 @@ export class CoreUserProvider {
      * @param search The string to search.
      * @param searchAnywhere Whether to find a match anywhere or only at the beginning.
      * @param page Page to get.
-     * @param limitNumber Number of participants to get.
+     * @param perPage Number of participants to get.
      * @param siteId Site Id. If not defined, use current site.
      * @return Promise resolved when the participants are retrieved.
      * @since 3.8