I am only noticing this problem on 4.2 EA2. I do not recall this problem on 4.1.
I see that when running Explain Plan (I usually use the F10 shortcut key), I often get ORA-00911: Invalid character errors. I finally played around with it and have reproduced the problem in various ways. It always seems to come down to having (a) multiple statements in the editor and (b) one of the statement is missing a semi-colon at the end of the statement.
For example. Consider the following three statement in the editor:
select 1 from dual;
select 1 from dual;
select 1 from dual
Since the ";" character is missing from line 5, NONE of the lines above will explain. Put cursor in line 1 and use F10. I get the ORA-00911 error. The same happens on lines 3 and 5. The only way to make Explain work is to go to Line 5 and insert the missing semi-colon. Even if i highlight line 3 only - I still get the error.
Again - I don't recall this on earlier builds. The frustrating part is that if I am missing a semi-colon anywhere in the editor, the Explain Plan fails.
Anyone else seeing the same behavior - so far I have not seen this reported on the forums. I have attached some additional screenshots. I am using Mac OS if that could be a culprit (although 4.1 on Mac OS did not have this problem)