I created procedure:
create or replace procedure PROC is
x varchar2(10);
y varchar2(10);
begin
x := ''; -- line 5
y := 'aaa'; -- line 6
end PROC;
and run 'Test' option on it. When debugger is before line 5 hint over 'x' is 'x = NULL'. After that line hint doesn't display over 'x', to be precise: it displays for a little while. I think, there is a problem with empty string value (''), because after line 6 there is hint over 'y': 'y = aaa'.
create or replace procedure PROC is
x varchar2(10);
y varchar2(10);
begin
x := ''; -- line 5
y := 'aaa'; -- line 6
end PROC;
and run 'Test' option on it. When debugger is before line 5 hint over 'x' is 'x = NULL'. After that line hint doesn't display over 'x', to be precise: it displays for a little while. I think, there is a problem with empty string value (''), because after line 6 there is hint over 'y': 'y = aaa'.