When editing a rule in expression mode, and searching for some text, the search control positions itself over the scroll window such that you cant easily scroll a single line to make the selected search result visible . Here's an example:
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yea, its designed this way ,for workaround you can expand the size of expression editor.
Yes, I think that's a good feature to find out where ever the words that we are looking for are placed in which lines through out the entire code. It will be helpful for you when you are having more LOC.
I typically use the mouse wheel to scroll.
Okay. But what's the question? If you need workarounds, you can scroll with arrow keys, mouse wheel or even a trackpad.