Plugins installed on Eclipse not visible

When I install a plugin in Eclipse everything goes well. But after restarting the new plugin is not visible. I have tried it with different plugins, but they have all the same problem. The only place where I can see them is when I look at "What is already installed?".

What could be the problem?

How do I see what plugins are installed in Eclipse?

One way of finding out is to select Help > About Eclipse Platform >. From this dialog, click Plug-in Details to get a list of all installed plug-ins, along with vendor and version information.

Where are Eclipse Marketplace plugins installed?

Eclipse traditionally puts plugins in the Eclipse install location in a 'plugins' directory. If that location is not writeable then a . eclipse directory in the user's home directory is used. For newer Eclipse installs using the Oomph installer a .

This issue and its solution is described in a DZone article and at the nWire blog.
It all boils down to these two options: