extension: sidebar glitches when search tab is open

[karlicoss]

The sidebar sometimes stops responding when search is open in background tab (or Vivaldi frame)

(reported by @bepolymathe)

[karlicoss]

don't think it's an issue anymore on master -- perhaps after fixing #103 -- will release to addon stores soon-ish

[karlicoss]

should be fixed now, couldn't reproduce with new version