When opening a script file, that is approximately 1016KB, or any similar sized files, in Editor all in one tab hangs Toad. This issue is persistent in version 9.6. Using version 9.5, file can be opened in Editor without any issues. This is a script file generated by Toad's sync script option.
If file is opened in individual tabs, it will result in over 300+ Editor tabs and version 9.6 has no issues.
Open file in individual Editor tabs or use version 9.5 of Toad to open file.
Waiting for fix in a future release of Toad for Oracle.