Cancel clicks if copy is active (#1300)

files/app/main/app.ut

@@ -85,6 +85,11 @@
                     }
                 }
             });
+            document.body.addEventListener("click", e => {
+                if (!document.getSelection().isCollapsed) {
+                    e.stopPropagation();
+                }
+            }, true);
         })();
     </script>
     {% } %}