Locate event target off screen, in case platform doesn't support opacity of text areas (Android 4, for example).

guacamole/src/main/webapp/styles/client.css

@@ -212,9 +212,17 @@ div#viewportClone {
     visibility: hidden;
 }
 
+/* Keyboard event target */
+
 textarea#eventTarget {
     position: fixed;
+   
+    /* Zero... zero... zero... zero... zero... */
+    right: 0;
+    bottom: 0;
     width: 0;
     height: 0;
     opacity: 0;
+
+    overflow: hidden;
 }