add no display for widget title

@kniebremser: This would fall outside the domain of Widget Customizer and would be a feature for widgets in general. In other words, if you add the Recent Posts widget via the Widgets admin page in the backend, and you leave the Title title blank, it will show “Recent Posts” as the widget title there as well.

There are three options for you:

1) use CSS to hide titles for Recent Posts widgets. For example: .widget_recent_entries .widgettitle { display: none; }

This is by far the easiest.

2) create a new widget that extends or copies the existing Recent Posts widget, but remove the title.

3) create (or find) a plugin which adds fields to every widget which allows you to opt-out of the widget title from being rendered for any widget.