diff --git a/app/src/main/java/io/timelimit/android/ui/manage/category/ManageCategoryFragment.kt b/app/src/main/java/io/timelimit/android/ui/manage/category/ManageCategoryFragment.kt
index fdf1b5e..b584b2b 100644
--- a/app/src/main/java/io/timelimit/android/ui/manage/category/ManageCategoryFragment.kt
+++ b/app/src/main/java/io/timelimit/android/ui/manage/category/ManageCategoryFragment.kt
@@ -75,13 +75,13 @@ class ManageCategoryFragment : Fragment(), FragmentWithCustomTitle {
         bottom_navigation_view.setOnNavigationItemSelectedListener {
             menuItem ->
 
-            pager.currentItem = when(menuItem.itemId) {
+            pager?.currentItem = when(menuItem.itemId) {
                 R.id.manage_category_tab_apps -> 0
                 R.id.manage_category_tab_time_limit_rules -> 1
                 R.id.manage_category_tab_blocked_time_areas -> 2
                 R.id.manage_category_tab_usage_log -> 3
                 R.id.manage_category_tab_settings -> 4
-                else -> 0
+                else -> throw IllegalStateException()
             }
 
             true
diff --git a/app/src/main/java/io/timelimit/android/ui/manage/child/ManageChildFragment.kt b/app/src/main/java/io/timelimit/android/ui/manage/child/ManageChildFragment.kt
index 2ac4209..ee637c0 100644
--- a/app/src/main/java/io/timelimit/android/ui/manage/child/ManageChildFragment.kt
+++ b/app/src/main/java/io/timelimit/android/ui/manage/child/ManageChildFragment.kt
@@ -79,11 +79,11 @@ class ManageChildFragment : Fragment(), FragmentWithCustomTitle {
         bottom_navigation_view.setOnNavigationItemSelectedListener {
             menuItem ->
 
-            pager.currentItem = when (menuItem.itemId) {
+            pager?.currentItem = when (menuItem.itemId) {
                 R.id.manage_child_tab_categories -> 0
                 R.id.manage_child_tab_apps -> 1
                 R.id.manage_child_tab_manage -> 2
-                else -> 0
+                else -> throw IllegalStateException()
             }
 
             true
diff --git a/app/src/main/java/io/timelimit/android/ui/overview/main/MainFragment.kt b/app/src/main/java/io/timelimit/android/ui/overview/main/MainFragment.kt
index 4ea4ef2..3d5b9ac 100644
--- a/app/src/main/java/io/timelimit/android/ui/overview/main/MainFragment.kt
+++ b/app/src/main/java/io/timelimit/android/ui/overview/main/MainFragment.kt
@@ -113,11 +113,11 @@ class MainFragment : Fragment(), OverviewFragmentParentHandlers, AboutFragmentPa
         bottom_navigation_view.setOnNavigationItemSelectedListener {
             menuItem ->
 
-            pager.currentItem = when(menuItem.itemId) {
+            pager?.currentItem = when(menuItem.itemId) {
                 R.id.main_tab_overview -> 0
                 R.id.main_tab_uninstall -> 1
                 R.id.main_tab_about -> 2
-                else -> 0
+                else -> throw IllegalStateException()
             }
 
             true