Very simple explanation.

Anything that is 100% transparent cannot be clicked. The text button uses a fully transparent graphic as its background. If you use the stylus you should find you can click on the pixels making up the text.

These configs were built before they added the option for a panel to be transparent.

Theer are 3 ways to place text on a transparent background:
- Use a button with a transparent background image, but you have to put an action on it to stop it being greyed out
- Use a panel with a transparent backround image
- Use a panel, with no background image, but mark it No Fill.

If they were doing it now, they would use the last option.

[Above has been edited since first posted]