Add missing '='

server/src/main/resources/VAADIN/vaadinBootstrap.js

@@ -368,7 +368,7 @@
             // This parameter is used in multiplatform-runtime as a key for
             // storing the MPR UI content in the session
             if (window.mprUiId) {
-                params += '&v-mui' + encodeURIComponent(window.mprUiId);
+                params += '&v-mui=' + encodeURIComponent(window.mprUiId);
             }
 
             // Detect touch device support