I recently set this up to display a WASD icon using Input Brush Key Sets, so here’s how I got it working. Note that I’m not using the Enhanced Input Support with CommonUI.
First, create a CommonUI Input Action Data Table and define your input actions there:
Create a CommonInputBaseControllerData asset and configure your Input Brush Key Sets (and optionally the Input Brush Data Map if needed):
Add the newly created Controller Data asset in Project Settings > Game > Common Input Setting > Platform Input:
Add a Common Action Widget in your Widget Blueprint, and assign all input actions that are mapped to the keys defined in your Brush Set:
The Action Widget on the right (green square) has multiple Input Actions assigned. It will automatically look up the corresponding icon in the Input Brush Key Sets and display the combined brush (for example, the WASD icon).
The widgets on the left are just showing the regular single-key icons via the Input Brush Data Map. For them to show you need to configure the Input Brush Data Map.
Result:
