diff --git a/src/dyn_object.cpp b/src/dyn_object.cpp
index 4d3faa4..88d1baf 100644
--- a/src/dyn_object.cpp
+++ b/src/dyn_object.cpp
@@ -13,7 +13,9 @@ int DynObject::event_filter_handle = 0;
 QObject* DynObject::currentSender  = 0;
 
 DynObject::DynObject(QObject* par) : QObject(par), event_filters(false) {
-    qApp->installEventFilter(this); }
+    // note: QADD-EVENT-FILTER will not work if EQL5 is not running on the UI thread
+    if(thread() == QApplication::instance()->thread()) {
+        qApp->installEventFilter(this); }}
 
 int DynObject::qt_metacall(QMetaObject::Call c, int id, void** args) {
     if(QMetaObject::InvokeMetaMethod == c) {