Reporting a new Flex SDK or Flex Builder bug - Flex Open Source Information and Bug System Instructions

Step 1 - (Important) Look for an existing bug report that may be similar

This is a very important step. In order to avoid duplicate bugs in the system, you should always do a search for an existing bug report that already describes the issue or one that is very similar. If a similar bug report already exists, please follow these instructions to either Add information to an existing Bug or to Voting on existing bugs

Step 2 - Create New Issue

Step 3 - Pick a Good Bug Title - Sell Your Bug!

A good descriptive bug title is very important - it helps developers on the project identify related issues quickly and it makes it more likely that others in the community will find your bug and vote for it. (See: Voting on existing bugs)

Step 4 - Select the severity

Try to make your best guess here - again, good categorization means that others in the community will find your bug easily and will vote for it.

Step 5 - Select the component/area that you think the bug affects

Try to make your best guess here - again, good categorization means that others in the community will find your bug easily and will vote for it. You'll have to at least make your best guess here - but don't worry if you get this wrong. Once a bug report gets enough votes, it will enter a formal review process where the development team will confirm the correct categorization.

Also - this is where you should select the build number you were using when you discovered the bug
How to find the Flex SDK Build Number
How to find the Flex Builder Build Number

For Operating System: Choose the operating system version you were using when you discovered the bug. Developers on the project may change your selection if the bug reproduces on other platforms.

Step 6 - Provide detailed steps to reproduce the problem

Provide the exact steps someone would need to reproduce this issue - be as detailed as possible.
Try to work within the template as much as possible.

For Tips on writing good reproduction steps - see: Writing a Good Bug Report