Hello,
Yes, you can set the COLOR_A before widgets such as keys and it will set the alpha value to give them transparency.
Large buttons use quite a lot of Display List resources and so if your aim of the large button in the background behind the keys is just to detect if pressed between the keys, a tagged rectangle under the keys would do the same job. You can even make it invisible by setting the alpha to 0 if it is only for touch sensing purposes.
Alternatively, you can set the CLEAR_TAG before calling the CLEAR(1,1,1) at the start of the command list and this will set the tag which you get if you touch any area of the screen which is not containing a tagged object.
You can also make custom keys instead of the keys widget by using small equally sized bitmaps as bitmap cells (thereby allowing you to load many buttons on the same bitmap handle) and so could have icons or images on them.
Best Regards, FTDI Community