Argh! Reworked AccessibleButton key handling again. It turned out by

fixing behaviour when pressing the enter key breaks behaviour when
pressing space to activate the buttons. So we are now handling enter
onKeyDown and space onKeyUp. Also briefly explained the situation with
comments.

src/components/views/elements/AccessibleButton.js

@@ -16,6 +16,8 @@
 
 import React from 'react';
 
+import { KeyCode } from '../../../Keyboard';
+
 /**
  * AccessibleButton is a generic wrapper for any element that should be treated
  * as a button.  Identifies the element as a button, setting proper tab
@@ -27,8 +29,18 @@ import React from 'react';
 export default function AccessibleButton(props) {
     const {element, onClick, children, ...restProps} = props;
     restProps.onClick = onClick;
+    // We need to consume enter onKeyDown and space onKeyUp
+    // otherwise we are risking also activating other keyboard focusable elements
+    // that might receive focus as a result of the AccessibleButtonClick action
     restProps.onKeyDown = function(e) {
-        if (e.keyCode == 13 || e.keyCode == 32) {
+        if (e.keyCode === KeyCode.ENTER) {
+            e.stopPropagation();
+            e.preventDefault();
+            return onClick(e);
+        }
+    };
+    restProps.onKeyUp = function(e) {
+        if (e.keyCode === KeyCode.SPACE) {
             e.stopPropagation();
             e.preventDefault();
             return onClick(e);