I noticed that a while ago after an upgrade to 30-something: a weird cursor mark blinking on various areas on the page wherever I clicked - and not only an elements that are focused. I hated that but had no idea why.
To be short: this feature is called "Caret Browsing" and is intended to make all areas easily selectable even on touchscreens. This feature was (still is?) turned on by default. But you can switch it off with F7. You can also find the setting in the advanced settings, general under "accessibility" and it is called "Always use the cursor keys to navigate within pages". Just uncheck this option and you are done.
Lessons learned...
Author: Oliver Busse
http://about.me/oliverbusse
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