There is a need for a container widget to create and store selections of features that can be accessed later as the input for widgets. Feature selection can be similar to what is possible within the Batch Attribute Editor. The primary difference is that selections can be used as inputs for widgets.
Here are a few possibilities if current widgets were able to take in a global feature selection:
This is just the tip of the iceberg. Imagine how much more powerful apps and widgets would be with feature selections!