diff --git a/pv_app/src/application.hpp b/pv_app/src/application.hpp
index 1fb6e7d15e29e524d8cb37d64eff8ec13062f502..7a6ea6847f8ad0b1db85de33de9370b18d93b9af 100644
--- a/pv_app/src/application.hpp
+++ b/pv_app/src/application.hpp
@@ -33,9 +33,11 @@
 
 class QSplitter;
 
-namespace pv_app {
+namespace qpvt {
+  class perf_data_viewer_widget;
+}
 
-class perf_data_viewer_widget;
+namespace pv_app {
 
 //------------------------------------------------------------------------------
 class application