No recent files in GNOME Shell
Solution 1:
You can integrate file search into Gnome shell by installing this extension:
https://extensions.gnome.org/extension/62/journal/
If you also want your recently opened files in the jump list of the appropriate program (very handy) install this extension:
https://extensions.gnome.org/extension/33/jump-lists/
Make sure you have installed gir1.2-gnomedesktop-3.0
before installing the extension:
sudo apt-get install gir1.2-gnomedesktop-3.0
Solution 2:
This functionality was removed by GNOME developers in bug https://bugzilla.gnome.org/show_bug.cgi?id=670150. To get recent files back in search results you have to build and install gnome-shell from source with the two commits reverted or stick with gnome-shell 3.2.2.1 and Ubuntu 11.10 for foreseeable future, until replacement applications like gnome-documents gain some shape.
Solution 3:
You can install the extension Tracker Search. Make sure you install before the packages tracker
and gir1.2-tracker-0.14
.
Since Tracker will index every files in the folders you've configured, it's less efficient and accurate than searching among the recent files. Anyway, it's fast and works as expected : just open the Activities overview and type !
Solution 4:
Since a few weeks, you can use an extension called Search Recently Used Files which works as you want on Ubuntu 12.10 with GNOME Shell 3.6.
Contrary to gnome-document search provider, you can search among any type of documents from the activity overview and the results appear instantly.
Unfortunately, this extension seems not to be compatible with GNOME Shell 3.4 on Ubuntu 12.04 according to this file.