CAPTCHA Window Doesn't Open

[Zaxim]

I'm on Linux and using the Standalone Zotero 4.0.29.10 and the 1.9.1 version of the Add-On.
When I do a mass update of citations, I'm not sure if the search delay is sufficiently long, as I'm getting blocked fairly regularly. The add-on also never opens a window to solve the CAPTCHA, however, opening a window to scholar.google.com myself does present me with the CAPTCHA.

[Zaxim]

So a wrinkle in my reported issue. I've had several update requests fail without the CAPTCHA window opening up. However, on subsequent attempts to update citations, I do get the pop-up. So my amended issue is:

Sometimes when Update Citations are blocked the pop-up does not display. Other times it does.

[qwerty]

Thank you for developing and improving this essential Add-On.

I am using Zotero for Firefox 4.0.29.21 and 1.9.1.1 version of the Add-On on Windows 7 and I am experiencing the same issue: if I update all citations, I get blocked after about 10 items, and Captcha windows doesn't open. If I manually open it and unlock the Google service and click again on "Update all citations", it gets again blocked after only a few items.

Would it be possible to increase the pause between every item? Even if it takes 10 times more but it is stable, it would be much more effective.