MacOS – How to remap F4 to Dashboard or Notifications on a MacBook Pro in Yosemite

I encountered the same problem, but now have a partial solution:

If you want to refresh the list entirely, delete the .db file located in "~/Library/Application Support/Dock/", followed by running killall Dock. This forces the Dock to refresh its list of widgets. Unfortunately, the list of apps in Launchpad will also be reset.

You can remove these individually via

sqlite3 ~/Library/Application\ Support/Dock/*.db "DELETE from apps WHERE title='APP_NAME';" && killall Dock

(from http://www.wikihow.com/Delete-Apps-from-Launchpad-in-Mac-Os-X-Lion, which adds:

 Replace APP_NAME with the name of the unwanted app as it’s displayed in LaunchPad.

)

I wish I knew how to add widgets manually, but I really don't know much unix... If it's any help to those trying to find a better solution, the widgets are located in /Library/Widgets.

Update

In the end I just decided to use Launchpad Manager to delete apps. It also functions as a widget manager.

I had tried this last year but then it didn't work. I tried it again and now it did work:

Start terminal and execute the following commands:

• defaults write com.apple.dock mcx-expose-disabled -bool FALSE (this enables mission control)
• killall Dock (kill and automatically restart the Dock, this is necessary to get it done)

There is an article about hot corners missing dashboard and mission control.