Going back to the old 0-0-0-0-0 method of hiding the text area... as doing otherwise causes issues with focus and "Enter" on Android.

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

@@ -218,8 +218,10 @@ textarea#eventTarget {
     position: fixed;
    
     /* Hide offscreen */
-    left: 100%;
+    left: 0;
-    top: 100%;
+    top: 0;
+    width: 0;
+    height: 0;
     opacity: 0;
 
     overflow: hidden;