For the Regular expression,no matter sender,body,subject,head,it is always Match Cases,even you edit,not select Match Cases,the result is always SELECTED

This is because the Case-Sensitivity does not apply when operator is set to Regular Expression. You can make the expression case sensitive/insensitive by tweeking the actual expression.

Even you edit the rule and change it to be: insensitive,the final result is always sensitive.

You can never change it to be insensitive if it is Regular expression