User has the option, "Execute Querries in Threads" checked, but it will de-select itself when sorting columns in the Data tab of the table in the Schema Browser while a query or procedure is running.
Follow the steps below to re-create the issue:
1. Ensure that in the options, Execute Querries in Threads is Checked.
2. Open a session and a sql query window, find a long running query and load it into editor.
NOTE: You can safley use this procedure to test in the Editor:
DBMS_LOCK.sleep(seconds => 10.01);
3. Execute the loaded query using the Execute Statement button.
4. While the query is running navigate to a schema browser window and choose the data tab for any table.
5. Click one of the column headings to sort it and and error pops up saying "a query is executing in single -thread mode".
6. The only option at this point is to click OK in the error dialog.
7. After the query is completed check your options again and you'll find that the Execute Querries in Threads has been unchecked by Toad.
Use the Execute as Script to execute your script or procedure.
Run the script in Script Runner (QSR): Go to Editor | Execute SQL via QSR in Toad main menu.
Click on the 'Table Sort/Filter' button (funnel icon) and sort in the dialogue box.
NOTE: It may take more system resources using this method.
Waiting for fix to be released in a future version of Toad for Oracle.