I checked this after a clean reboot.
I run Codea app, i open Andrew_Stacey’s cube project and with any tab opened i click the function key, it takes like 20secs to show the function browser and when scrolling down i reach the class Font8x16 it always crashes.
Then I created a new project importing only the Font class and Font8x16 class and it also crashes.
I attach the crash log:
http://pagantongue.posterous.com/function-button-crash
FWIW I experienced crashes like this when in a project I had some some commented out functions bearing the same names as live functions in other tabs. Renaming the commented out functions fixed the problem. 
I’m not saying that this is what is happening in Andrew’s code but I have been able to replicate the crash…
@Stavrogin this is fixed in the next version (the crash, it’s still slow to open on large projects like @Andrew’s).
Edit: It happens because the parser mishandles anonymous functions, so any code with anonymous functions causes it.