What version of Selenium Core is Selenium IDE based on?

There are no relations between version numbers of Selenium IDE and Selenium. Some versions of Selenium IDE use unreleased versions of Selenium Core. You can check the version of Selenium Core for each version of Selenium IDE at http://www.openqa.org/selenium-ide/download.action

Is there an IE version of Selenium IDE?

No, at this time Selenium IDE works for Firefox only. You can write your test scripts via IDE and then use the Selenium Core/TestRunner to execute them on IE.

Why doesn't everything I do get recorded?

Not every event will be recorded by Selenium IDE. Usually the ones that won't be recorded are those that involve complex HTML and/or AJAX. We hope to improve this over time, but there will always be situations where the IDE can't record everything because it has to balance recording too little with too much.

You are encouraged to get used to the Selenium commands and use Selenium IDE's excellent editor capabilities to piece together your test by hand. We recommend you use the "Find" button to verify your element locators as you are doing this.

Firefox 2 (2.0.0.3) has a bug: text field input that you auto-complete from history does not generate the normal JavaScript event. So, Selenium IDE cannot record it. The work-around is to manually finish typing the input, instead of selecting from auto-complete.