I just did:

1. sudo add-apt-repository ppa:webapps/preview

2. sudo apt-get update

3. sudo apt-get dist-upgrade

4. sudo apt-get install unity-webapps-preview

and get the following message:

Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:

The following packages have unmet dependencies: unity-webapps-preview : Depends: xul-ext-unity but it is not going to be installed Depends: xul-ext-websites-integration but it is not going to be installed Depends: xul-ext-webaccounts but it is not going to be installed E: Unable to correct problems, you have held broken packages.

What is wrong?