These nice Flex tips were posted by David Zuckerman, mirroring here for my convenience.

http://davidzuckerman.com/adobe/2006/10/27/flex-builder-editor-cheat-sheet

1.) Open type (Ctrl-Shift-T)* - this lets you browse all the types (AS classes/interfaces, MXML files) in your project and quickly open them.

2.) Goto Definition (F3/Ctrl-click on identifier)* - quickly jump to the definition of an identifier (type/variable/function).

3.) Quick Outliner (Ctrl-O)* - get the outline view as a pop-up window, with the added ability to type and filter down to the function/member variable that you’re looking for.

4.) Context sensitive help (F1 on an identifier/tag) - for an MXML tag, function or class/interface, show the help entry for that item in the Eclipse Help Panel.

5.) Open context sensitive help (Shift-F2 on an identifier) - for an MXML tag, function or class/interface, show the help entry for that item in the integrated Help browser. This will most likely open a new browser window.

6.) Jump to matching brace (Ctrl-Shift+P)* - jumps to the matching brace if your cursor is to the left or right of a given balanced brace.

7.) Hover over an identifier - when you put your mouse over a variable, we display its type. When you hover over a function, we display its return type (if it has one).

8.) Add CDATA block (Ctrl-Shift-C) in MXML - wraps a given selection in a CDATA block

9.) Event type hinting (Ctrl-space) - addEventListener( will display all the events that are relevant targets for a listener function.

10.) Fold all functions/ASDoc comments/comments in ActionScript - With folding enabled, right-click on the vertical gutter, drill down to “Folding”

11.) Organize imports (Ctrl + Shift + O)* - Sorts the imports in ActionScript files, removes duplicates and consolidates when needed