diff --git a/README.md b/README.md
index 33acacf..236924f 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,8 @@ Luigi Baldoni \<aloisio@gmx.com\>		: Initial setup of the OpenSuSE Build Service
 
 ## Known issues
 
+- SysTray does not work  when the Thunderbird title bar is disabled.  
+
 - SysTray-X preferences will be lost when moving from an old Thunderbird version to Thunderbird version 91 or higher due to the storage type change. As of SysTray-X version 0.8.0 the add-on will use the local storage type instead of the sync type.  
 Please press the reset button in the TB SysTray-X add-on preferences page to clear the old storage before setting your preferences again.