diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index e20a743e..f602d5c9 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,6 +1,10 @@
 Changelog
 =========
 
+1.7.21 (Unreleased)
+-------------------------
+- Fix #629: Fix sidebar widget issue
+
 1.7.20 (October 20, 2025)
 -------------------------
 - Enh #608: Improved `Upcoming events` widget to include events from followed spaces and profiles
diff --git a/interfaces/event/AbstractCalendarQuery.php b/interfaces/event/AbstractCalendarQuery.php
index b4f691c6..588957fc 100644
--- a/interfaces/event/AbstractCalendarQuery.php
+++ b/interfaces/event/AbstractCalendarQuery.php
@@ -14,7 +14,6 @@
 use Exception;
 use humhub\modules\calendar\helpers\CalendarUtils;
 use humhub\modules\calendar\models\CalendarEntry;
-use humhub\modules\calendar\models\CalendarEntryParticipant;
 use humhub\modules\content\components\ContentContainerActiveRecord;
 use humhub\modules\user\models\User;
 use humhub\modules\content\components\ActiveQueryContent;
@@ -22,6 +21,7 @@
 use yii\base\Component;
 use yii\db\ActiveQuery;
 use yii\db\ActiveRecord;
+use yii\db\Query;
 
 /**
  * Created by PhpStorm.
@@ -786,11 +786,7 @@ protected function setupCriteria()
         }
     }
 
-    /**
-     * Sets up the date interval filter with respect to the openRange setting.
-     * This will also include all recurrent event roots if $expand is true and recurrence evets are supported
-     */
-    protected function setupDateCriteria()
+    protected function createDateCriteriaQuery(Query $query)
     {
         if ($this->_from) {
             $fromTime = clone $this->_from;
@@ -806,21 +802,21 @@ protected function setupDateCriteria()
             //Search for all dates with start and/or end within the given range
 
             if ($this->dateQueryType === static::DATE_QUERY_TYPE_DATE) {
-                $this->_query->andFilterWhere(['or',
+                $query->andFilterWhere(['or',
                     ['and', $this->getStartCriteria($this->_from, '<'), $this->getEndCriteria($this->_to, '>')],
                     ['and', $this->getStartCriteria($this->_from, '>='), $this->getStartCriteria($this->_to, '<')],
                     ['and', $this->getEndCriteria($this->_from, '>'), $this->getEndCriteria($this->_to, '<=')],
                     $this->isRecurrenceRootCondition(),
                 ]);
             } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_TIME) {
-                $this->_query->andFilterWhere(['or',
+                $query->andFilterWhere(['or',
                     ['and', $this->getStartCriteria($fromTime, '<'), $this->getEndCriteria($toTime, '>')],
                     ['and', $this->getStartCriteria($fromTime, '>='), $this->getStartCriteria($toTime, '<')],
                     ['and', $this->getEndCriteria($fromTime, '>'), $this->getEndCriteria($toTime, '<=')],
                     $this->isRecurrenceRootCondition(),
                 ]);
             } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_MIXED) {
-                $this->_query->andFilterWhere(
+                $query->andFilterWhere(
                     ['or',
                         ['or',
                             ['and',
@@ -847,11 +843,11 @@ protected function setupDateCriteria()
         } else {
             if ($this->_from) {
                 if ($this->dateQueryType === static::DATE_QUERY_TYPE_DATE) {
-                    $this->_query->andWhere(['or', $this->getStartCriteria($this->_from, '>='), $this->isRecurrenceRootCondition()]);
+                    $query->andWhere(['or', $this->getStartCriteria($this->_from, '>='), $this->isRecurrenceRootCondition()]);
                 } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_TIME) {
-                    $this->_query->andWhere(['or', $this->getStartCriteria($fromTime, '>='), $this->isRecurrenceRootCondition()]);
+                    $query->andWhere(['or', $this->getStartCriteria($fromTime, '>='), $this->isRecurrenceRootCondition()]);
                 } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_MIXED) {
-                    $this->_query->andWhere(
+                    $query->andWhere(
                         ['or',
                             ['and', [$this->allDayField => 0], $this->getStartCriteria($fromTime, '>=')],
                             ['and', [$this->allDayField => 1], $this->getStartCriteria($this->_from, '>=')],
@@ -863,11 +859,11 @@ protected function setupDateCriteria()
 
             if ($this->_to) {
                 if ($this->dateQueryType === static::DATE_QUERY_TYPE_DATE) {
-                    $this->_query->andWhere(['or', $this->getEndCriteria($this->_to, '<='), $this->isRecurrenceRootCondition()]);
+                    $query->andWhere(['or', $this->getEndCriteria($this->_to, '<='), $this->isRecurrenceRootCondition()]);
                 } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_TIME) {
-                    $this->_query->andWhere(['or', $this->getEndCriteria($toTime, '<='), $this->isRecurrenceRootCondition()]);
+                    $query->andWhere(['or', $this->getEndCriteria($toTime, '<='), $this->isRecurrenceRootCondition()]);
                 } elseif ($this->dateQueryType === static::DATE_QUERY_TYPE_MIXED) {
-                    $this->_query->andWhere(
+                    $query->andWhere(
                         ['or',
                             ['and', [$this->allDayField => 0], $this->getEndCriteria($toTime, '<=')],
                             ['and', [$this->allDayField => 1], $this->getEndCriteria($this->_to, '<=')],
@@ -880,6 +876,15 @@ protected function setupDateCriteria()
         }
     }
 
+    /**
+     * Sets up the date interval filter with respect to the openRange setting.
+     * This will also include all recurrent event roots if $expand is true and recurrence evets are supported
+     */
+    protected function setupDateCriteria()
+    {
+        $this->createDateCriteriaQuery($this->_query);
+    }
+
     /**
      * Returns a sql condition filtering recurrent root events if supported. Returns empty string if not supported.
      *
@@ -1128,6 +1133,11 @@ public function filterIsParticipant()
         throw new FilterNotSupportedException('Participant filter not supported for this query');
     }
 
+    public function filterOrIsParticipant()
+    {
+        throw new FilterNotSupportedException('Participant filter not supported for this query');
+    }
+
     /**
      * Can be used to pre filter the result list
      * @param $result
diff --git a/models/CalendarEntryQuery.php b/models/CalendarEntryQuery.php
index 06b924c5..b78176c8 100644
--- a/models/CalendarEntryQuery.php
+++ b/models/CalendarEntryQuery.php
@@ -5,6 +5,7 @@
 use humhub\modules\calendar\interfaces\recurrence\AbstractRecurrenceQuery;
 use humhub\modules\content\components\ContentContainerActiveRecord;
 use DateTime;
+use yii\db\Query;
 
 /**
  * CalendarEntryQuery class can be used for creating filter queries for [[CalendarEntry]] models.
@@ -95,10 +96,17 @@ public function filterIsParticipant()
     public function filterOrIsParticipant()
     {
         $this->participantJoin();
-        $this->_query->orWhere(['calendar_entry_participant.participation_state' => [
-            CalendarEntryParticipant::PARTICIPATION_STATE_ACCEPTED,
-            CalendarEntryParticipant::PARTICIPATION_STATE_MAYBE,
-        ]]);
+        $onlyParticipatingQuery = new Query();
+        $this->createDateCriteriaQuery($onlyParticipatingQuery);
+
+        $this->_query->orWhere([
+            'AND',
+            ['IN', 'calendar_entry_participant.participation_state', [
+                CalendarEntryParticipant::PARTICIPATION_STATE_ACCEPTED,
+                CalendarEntryParticipant::PARTICIPATION_STATE_MAYBE,
+            ]],
+            $onlyParticipatingQuery->where
+        ]);
     }
 
     private function participantJoin()
diff --git a/module.json b/module.json
index 3705bdc0..1dee67c7 100644
--- a/module.json
+++ b/module.json
@@ -3,7 +3,7 @@
     "name": "Calendar",
     "description": "Create one-time or recurring events, invite and manage attendees, and keep track of all your events with the Calendar module.",
     "keywords": ["calendar"],
-    "version": "1.7.20",
+    "version": "1.7.21",
     "humhub": {
         "minVersion": "1.17.0-beta.4"
     },