diff --git a/app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.kt b/app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.kt
index b86bbde4d..e9f48a8c2 100644
--- a/app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.kt
+++ b/app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.kt
@@ -11,12 +11,17 @@ import com.todoroo.astrid.data.Task
 import com.todoroo.astrid.data.Task.Companion.HIDE_UNTIL_SPECIFIC_DAY
 import org.tasks.BuildConfig
 import org.tasks.LocalBroadcastManager
-import org.tasks.data.*
+import org.tasks.data.CaldavDao
+import org.tasks.data.CaldavTask
+import org.tasks.data.GoogleTask
+import org.tasks.data.GoogleTaskDao
+import org.tasks.data.SubsetCaldav
+import org.tasks.data.SubsetGoogleTask
+import org.tasks.data.TaskContainer
 import org.tasks.date.DateTimeUtils.toAppleEpoch
 import org.tasks.date.DateTimeUtils.toDateTime
+import org.tasks.tasklist.SectionedDataSource.Companion.HEADER_COMPLETED
 import org.tasks.time.DateTimeUtils.millisOfDay
-import java.util.*
-import kotlin.collections.HashSet
 
 open class TaskAdapter(
         private val newTasksOnTop: Boolean,
@@ -26,7 +31,7 @@ open class TaskAdapter(
         private val localBroadcastManager: LocalBroadcastManager) {
 
     private val selected = HashSet<Long>()
-    private val collapsed = HashSet<Long>()
+    private val collapsed = mutableSetOf(HEADER_COMPLETED)
     private lateinit var dataSource: TaskAdapterDataSource
 
     val count: Int
@@ -48,14 +53,14 @@ open class TaskAdapter(
 
     fun clearSelections() = selected.clear()
 
-    fun getCollapsed(): MutableSet<Long> = HashSet(collapsed)
+    fun getCollapsed() = HashSet(collapsed)
 
     fun setCollapsed(groups: LongArray?) {
         clearCollapsed()
         groups?.toList()?.let(collapsed::addAll)
     }
 
-    fun clearCollapsed() = collapsed.clear()
+    fun clearCollapsed() = collapsed.retainAll(listOf(HEADER_COMPLETED))
 
     open fun getIndent(task: TaskContainer): Int = task.getIndent()
 
diff --git a/app/src/main/java/org/tasks/tasklist/SectionedDataSource.kt b/app/src/main/java/org/tasks/tasklist/SectionedDataSource.kt
index ad58f6712..2a2c2ff76 100644
--- a/app/src/main/java/org/tasks/tasklist/SectionedDataSource.kt
+++ b/app/src/main/java/org/tasks/tasklist/SectionedDataSource.kt
@@ -6,13 +6,12 @@ import com.todoroo.andlib.utility.DateUtilities.now
 import com.todoroo.astrid.core.SortHelper
 import org.tasks.data.TaskContainer
 import org.tasks.time.DateTimeUtils.startOfDay
-import java.util.*
 
 class SectionedDataSource constructor(
         tasks: List<TaskContainer>,
         disableHeaders: Boolean,
         val sortMode: Int,
-        private val collapsed: MutableSet<Long>
+        private val collapsed: Set<Long>
 ) {
     private val tasks = tasks.toMutableList()
 
diff --git a/app/src/main/java/org/tasks/widget/ScrollableViewsFactory.kt b/app/src/main/java/org/tasks/widget/ScrollableViewsFactory.kt
index d1426fdf6..fee2a07a0 100644
--- a/app/src/main/java/org/tasks/widget/ScrollableViewsFactory.kt
+++ b/app/src/main/java/org/tasks/widget/ScrollableViewsFactory.kt
@@ -28,6 +28,7 @@ import org.tasks.markdown.Markdown
 import org.tasks.preferences.DefaultFilterProvider
 import org.tasks.preferences.Preferences
 import org.tasks.tasklist.SectionedDataSource
+import org.tasks.tasklist.SectionedDataSource.Companion.HEADER_COMPLETED
 import org.tasks.time.DateTimeUtils.startOfDay
 import org.tasks.ui.CheckBoxProvider
 import timber.log.Timber
@@ -70,7 +71,7 @@ internal class ScrollableViewsFactory(
     private var showLists = false
     private var showTags = false
     private var isRtl = false
-    private var collapsed = HashSet<Long>()
+    private var collapsed = mutableSetOf(HEADER_COMPLETED)
     private var sortMode = -1
     private var tasks = SectionedDataSource(emptyList(), false, 0, collapsed)
     private val widgetPreferences = WidgetPreferences(context, preferences, widgetId)
@@ -97,7 +98,7 @@ internal class ScrollableViewsFactory(
                     collapsed
             )
             if (collapsed.retainAll(tasks.getSectionValues())) {
-                widgetPreferences.collapsed = collapsed
+                widgetPreferences.setCollapsed(collapsed)
             }
         }
     }
@@ -368,7 +369,7 @@ internal class ScrollableViewsFactory(
         widgetPreferences.sortMode.takeIf { it != sortMode }
                 ?.let {
                     if (sortMode >= 0) {
-                        widgetPreferences.collapsed = HashSet()
+                        widgetPreferences.setCollapsed(mutableSetOf(HEADER_COMPLETED))
                     }
                     sortMode = it
                 }
diff --git a/app/src/main/java/org/tasks/widget/WidgetClickActivity.kt b/app/src/main/java/org/tasks/widget/WidgetClickActivity.kt
index ada7c79b3..328017ae3 100644
--- a/app/src/main/java/org/tasks/widget/WidgetClickActivity.kt
+++ b/app/src/main/java/org/tasks/widget/WidgetClickActivity.kt
@@ -75,7 +75,7 @@ class WidgetClickActivity : InjectingAppCompatActivity(), OnDismissHandler {
                 } else {
                     collapsed.remove(group)
                 }
-                widgetPreferences.collapsed = collapsed
+                widgetPreferences.setCollapsed(collapsed)
                 localBroadcastManager.broadcastRefresh()
                 finish()
             }
diff --git a/app/src/main/java/org/tasks/widget/WidgetPreferences.java b/app/src/main/java/org/tasks/widget/WidgetPreferences.java
index 5afda284e..cd4576b8e 100644
--- a/app/src/main/java/org/tasks/widget/WidgetPreferences.java
+++ b/app/src/main/java/org/tasks/widget/WidgetPreferences.java
@@ -92,7 +92,7 @@ public class WidgetPreferences implements QueryPreferences {
     return getIntegerFromString(R.string.p_widget_due_date_position, 0);
   }
 
-  public void setCollapsed(HashSet<Long> collapsed) {
+  public void setCollapsed(Iterable<Long> collapsed) {
     setString(R.string.p_widget_collapsed, Joiner.on(",").join(collapsed));
   }