Bringing this old thread back and I think it's somewhat related. I have my Captivate for months and started noticing this issue. My phone is not rooted, and factory upgraded to 2.2.
From time to time, the search function gets executed by itself for no reason. Sometime it gets called when I was typing text, and sometime it gets called when it sits idle (waiting for lock screen comes up).
This is my second Captivate as first one had screen issue so Rogers (Canada wireless provider) sent me this one with 2.2 firmware.
Any thought folks?