I have a control surface with touch sensitive faders and I want to know via a GPScript callback when the user touch the faders (e.g. to display a submix name on the control surface LCD when the fader is touched). So, as I don’t want to see a button or switch widget for this, I use the TextLabel Widgets which numbers the slices of the mixer panel which represents the control surface.
A more advanced use is to MIDI learn a TextLabel Widget to a Local GP Port message generated by a Scriptlet (it is away to « bridge » a Scriptlet MIDI output to a plugin parameter) like in the PluginPersist scriptlet:
Example of using the transparency to display which Pad is triggered ([Gig] NotesConverter for MIDI pads):