Twenty Fourteen: Ephemera Widget caches plugin filtering (and lack of plugin filtering) of the_content

[celloexpressions]

Many plugins filter the_content() to add things like social sharing buttons.

The Twenty Fourteen Ephemera Widget currently ignores the potential for plugins to change the contents of the widget. For plugins that rely on external css/js files for their functionality, deactivating the plugin will remove those assets but leave the html markup displayed. This creates a bad user experience because the plugin appears to not be removed even after deleting all of its files.

Example steps to reproduce:

1. Install & activate a plugin such as ​QuickShare
2. Add the Twenty Fourteen Ephemera Widget to a sidebar
3. Uninstall QuickShare

The html needed by QuickShare is still present in the widget. Removing and re-adding the widget fixes it.

One solution would be to prevent plugins' filters from ever applying to the widget's the_content, as they are almost never desirable for display in a widget. I'm currently hiding QuickShare from the widget with css.

[dimadin]

Related (duplicate?): #26210

[lancewillett]

In 26577:

Twenty Fourteen: remove transient usage in Ephemera widget to fix caching issues. Props obenland, closes #26210 and #26335.