Thx for info. Will test it later.
In the meantime I found out the possible error cause in this plugin - the importing of browser in that init was superfluous, as there were two similar calls:
br = browser()
br = self.browser
In Worker __init__, there's self.browser = browser.clone_browser()
So simple replacing of first line with self.browser and removing import caused all problems to vanish.
Yes, this plugin would need some code cleanup
