I have a components and classes project library. Within the library, flex builder only seems to display content/code assist options for top level classes (e.g. arguments, Array) but not other classes such as VBox. Also, within the non top level classes, class properties are not provided by content assist.
In my other flex projects in the workspace, content assist works fine.
Any help would be greatly appreciated!
Flex / Flash Builder is often inconsistent in stuff like this; but I have never seen the exact situation you describe.
Have you tried closing down and relaunching Flex Builder?
Have you tried launching Flex Builder with the '-clean' attribute?
Have you tried cleaning your workspace?
Are you sure you do not have a syntax error somewhere causing issues? Are all the classes in the library included in your library class? Sometimes error don't show up if the class is not used, and therefore not compiled into the file SWC.
Did you save your source files? I don't think Eclipse updates its index until you save - so, if you just wrote class X with function Y, but didn't save X.as, then Eclipse won't know what to do with X.Y(...
Sometimes when I've run into the problem you're describing, it's been because FB wasn't able to determine what type of object I was using (for example, obj["toto"] = ?).
Another idea may be to update your version of eclipse ("Software Updates" or something like that under the Help menu).
Finally, there's an annoying issue that happens to me sometimes where the content assist will appear for about half a second, then disappear like the window tried to scroll and lost the pop-up. Do you get anything when you press Ctrl-Space?