debugging oracle store proc

I already have SQL Developer in my system but i am not sure how to debug the proc.
I click on Debug but i am not able to put break points on the cursor.

Adding to tosse, when a procedure is compiled, choose the DEBUG option.  Googling for "how to debug pl sql code in sql developer", try something like http://www.oracle.com/webfolder/technetwork/tutorials/obe/db/sqldev/r30/plsql_debug_OBE/plsql_debug_otn.htm

>>By right clicking in this marging you can set breakpoints, then use the Run menu to step into/over etc. as usual when debugging.


thanks , i can also do right click-->toggle break point to set the breakpoint.
However when i click Run--> TRADE_PROC_BODY   (which is my procedure body)

I see 'Source does not have a runnable target.'  message on myconsole

any idea?

thanks

just to make it more clear this is what i have

i have created a package. My package body is called 'TRADE_PROC' body
In 'TRADE_PROC' body  i have

....
...
CURSOR tr_task IS   -- i put a break point here  
SELECT task_id from task_table;
 
 BEGIN
 OPEN  tr_task;   --put a break point here  
 FETCH tr_task BULK COLLECT INTO task_def_id;

but when  i click Run or Debug option i see
Source does not have a runnable target.