How to debug a SMARTFORM

1- Tcode > smartforms > F8>

2- You will get a FM exp : /1BCDWB/SF00000138

3- Go to SE38 and add 'L' before S and add 'F01' and the end.  So this will become /1BCDWB/LSF00000138F01

4 - Now add break point where ever you want