The recent update in WordPress brought a weird but totally fixable bug.
A Google search showed that I was not alone having the disappearing Visual Mode in my WordPress dashboard. And the same search showed a very quick fix for this problem.
I simply installed the “use Google Libraries” plugin, activated it, cleared my cache and then went back to the editing dashboard, clicked Visual, then HTML and then back to Visual and the toolbar appeared!
If that doesn’t fix the problem for you, one of the suggestions was to:
1. Install “use Google Libraries” plugin.
2. Activate “Twenty Eleven” Theme. Caution here – sometimes you can lose the customizations of your current theme so be sure you make a complete backup of all of your settings.
3. Clear the browser cache.
4. Try the tabs and make sure they work.
5. Switch back to your theme and make sure everything is still working.
I just installed the plugin and cleared my cache and that fixed the problem.