Idea Summary
Native editing of filter expressions in Interactive Grid / Interactive Report Search Field is desired feature, and it is one of the user-friendly features in all famous web applications 

Use Case
After searching with an Expression in search field, if we want to try another expression, 
need to click the “X” and wait , because this is taking huge amount of time to reload the data.

This selection process consuming lots of time especially with long-running reports to "try" out" their filter criteria

Preferred Solution (Optional)
Clicking the expression itself could open a dialog box with a text input and an [Apply] button. 
The new expression would then replace the former one immediately.