diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/add/AdditionalLessonAddDialog.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/add/AdditionalLessonAddDialog.kt
index 134719979..9a84fb0a2 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/add/AdditionalLessonAddDialog.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/add/AdditionalLessonAddDialog.kt
@@ -155,7 +155,9 @@ class AdditionalLessonAddDialog : BaseDialogFragment<DialogAdditionalAddBinding>
             .build()
 
         timePicker.addOnPositiveButtonClickListener {
-            onTimeSelected(LocalTime.of(timePicker.hour, timePicker.minute))
+            if (isAdded) {
+                onTimeSelected(LocalTime.of(timePicker.hour, timePicker.minute))
+            }
         }
 
         if (!parentFragmentManager.isStateSaved) {