Add text field event target, focus event target if "Show Keyboard" is clicked and use exposed the menu via long-press. Ensure backspace always sends a key event by always keeping text within the event target.

guacamole/src/main/webapp/client.xhtml

@@ -54,6 +54,10 @@
 
         </div>
 
+        <input id="eventTarget"
+               type="text"
+               style="width: 0; height: 0; position: fixed; opacity: 0"
+               value="x"/>
 
         <!-- Display -->
         <div id="display">