diff --git a/forms/source/richtext/richtextengine.cxx b/forms/source/richtext/richtextengine.cxx
index 25f1b185e67b..82858195eb84 100644
--- a/forms/source/richtext/richtextengine.cxx
+++ b/forms/source/richtext/richtextengine.cxx
@@ -46,6 +46,8 @@ namespace frm
     //--------------------------------------------------------------------
     RichTextEngine* RichTextEngine::Create()
     {
+        SolarMutexGuard g;
+
         SfxItemPool* pPool = EditEngine::CreatePool();
         pPool->FreezeIdRanges();