Why is Sublime Text context menu disabled (image below)

I have installed HTML-CSS-JS Prettify package in Sublime Text 3 (on Ubuntu 18.4). The image below shows that it appears on the context menu. However, when I select its context menu (the second context menu) has all options greyed out. I can't find a explanation anywhere and would appreciate knowing how to enable it.

If it is any use the "Anaconda" selection is also all greyed out when I select it. Nodejs is not.

Many thanks.

Menu items appear disabled for a couple of different reasons.

The first (and most common) is that when a menu is about to be displayed, Sublime asks every command bound to an item available in the menu if it should be enabled right now or not, and the command can decide to disable itself if it currently doesn't apply.

The second reason is that the command bound to the menu item is currently missing. For people using packages and not creating them themselves, that generally means that there's something wrong with the plugin that provides the command, such as it not loading for some reason.

In this case, based on the items in there it seems more likely that the second case is what's getting you here.

In order to check that, use View > Show Console or the associated key binding and see if there are any messages that look like a package didn't load for some reason. If so, resolving whatever issue that is should get things working.