I have released an update that implements usage of chrome.storage.local for the tree data. From the changelog:

## 2017.2.12.0

* Fix a problem where Sidewise tree data could get corrupted if it exceeded several thousand total tabs. Sidewise should now be able to store an essentially unlimited number of tabs.

Please try out the new version and let me know how it goes for you.

Hi all, I have a fix for the localstorage limitation / data loss problem implemented and am testing it now. Apologies for the very extended delay.