Bug! toad for oracle datagrid show chinese error！！

SQL Optimizer Idea Pond
1

I'm chinese,
toad for oracle 11.6 or toad 16.2 for oracle show chinese error .
plsql develop right. why!??
I set NLS_LANGUAGE='AMERICAN_AMERICA.US7ASCII'
but in invalid.
please tell me think you ！
my mail 350832289@qq.com