Image button for touch screen applications
 For a touch screen application, I am using images to let the user enter numbers by clicking on the images (one for each digit). But when I want to fill in 12 (for example) in an inputfield with the buttons (images) on the screen the previous number is deleted. So instead of getting 12, I first get 1; this is then deleted and I get 2. (When I touch 1 and then 2).

Images can only be used to fill in the whole field value. To add a digit, combine  the image with an InputScript:

Example:

Image (10,20) "one.gif" Input="U[DIGIT]:1;OK,process=enterdigit.txt"
Image (10,24) "two.gif" Input="U[DIGIT]:2;OK,process=enterdigit.txt"

// InputScript enterdigit.txt:

Parameter DIGIT
set [Material] "&F[Material]&U[DIGIT]"
Return

In a similar way, you can also create a "CLEAR" and "BACK" button.