When I am focused in the box of the Filter and write anything, no matter if with or without Auto-apply filter option turned on, then that box gets blocked - i.e. it no longer registers movement of mouse wheel thus do not scroll through the list of filtering expressions. In order to unblock the mouse wheel for that feature I have to first click within the box
This happens also no matter if after writing a new expression I stay with focus / prompt in Filter box, hover mouse pointer somewhere or click on a file from presented list - a click within the box is always required in order for me to able to scroll the list with my mouse wheel
I do not see anything "blocking" the filter box.
A "blocking" would mean to me that no further input is ever possible.
This is not the case as functions are immedidately available after another click into the filter box.
The behaviour that you describe applies to any combo-box. As soon as you change to edit mode, mouse wheel scrolling is disabled.
You can recognize the edit mode that the selection disappears and the keyboard cursor appears.
If you click into that combo-box again, the mouse wheel functions are available again.
You may test this behaviour e.g.with any field in the tag panel where you cannot scroll to <keep> and <delete> once you have started editing. You would have to click into that field again or press Cursor down
I do not think that the developer has any obligations to disclose his plans to you how the program develops further.
As this function looks a lot like a function supplied by Windows, I would kindly ask you to forward your bug report to Microsoft and see how and what they answer and which planned dates they reveal to you.