diff --git a/htdocs/css/openwebrx.css b/htdocs/css/openwebrx.css
index ffd0419..30028b2 100644
--- a/htdocs/css/openwebrx.css
+++ b/htdocs/css/openwebrx.css
@@ -998,6 +998,7 @@ img.openwebrx-mirror-img
 
 .openwebrx-dmr-timeslot-panel * {
     cursor: pointer;
+    user-select: none;
 }
 
 .openwebrx-ysf-mode:not(:empty):before {