Ok, this one's a bit weird...
The settings page of the plugin (chrome-extension://kkelicaakdanhinjdeammmilcgefonfh/settings.html) show up in a new tab randomly while browsing another page.
I don't know how it could be related, but I can replicate the bug while browsing my angular.js page using UI Bootstrap Tabs library (https://angular-ui.github.io/bootstrap/#/tabs), and cycling through my tabs. The bug happens when clicking on 1st tab's header. I could not replicate the bug on the library's demo page though, and I can't link you to source product yet (company's policy).
I tried to disable keyboard shortcuts for your plugin, with no effect.
Any ideas? I can try to copy a fragment of my code into a demo page if needed.
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