I've seen an issue a few different installations whereby the Open Resoure
menu open in Navigate
appears twice, which wouldn't be a problem if it didn't disable the CTRL+SHIFT+R
shortcut to it.
I've seen it affect both Flex Builder 3 and Flash Builder 4, but it only seems to affect the standalone version when it is installed after the plugin version. Re-installation doesn't seem to help.
NOTE: I'm posting this with the intent of self-answering