I think that, due to latest Trusty s/w updates, none of my applications (including standard Trusty installed ones) are available from the Dash! Or have I done something to cause this? The Applications category is enabled on Categories & Sources. PS this is only happening on my desktop i.e. not on my laptop. Both computers had clean installs of Trusty.
This issue was reported in Ubuntu Forums in 2011. The problem appears to be a corrupted .cache. I removed $HOME/.cache and after a log out/log in, dash went back to its normal behaviour.