Sidewise won't launch anymore

Sidewise won't launch anymore. The icon is still there but nothing would happen when you click it.

I've been using Sidewise for about 2 months and have accumulated more than a thousand hibernated tabs. Before this problem of Sidewise not launching occurred I'd noticed that some of tabs I opened were not appearing in Sidewise. But, when I restarted Chrome and reloaded the last session tabs, the tabs previously not appearing could now be seen in Sidewise.

But now when I click Sidewise icon nothing happens. I tried restarting Chrome and also restarting computer but it still won't work. I'd like to try reinstalling Sidewise but I'm afraid that I might lose my hibernated tabs.

Please advise on how can I make Sidewise work again or how to recover my hibernated tabs. Thanks in advance.