Ok, I think I've tracked it down now.
The problemAn unwanted scrollbar appears and hides part of the result text only when
(1) the search matches a regex alias and
(2) the regex alias has only one result and
(3) the search before the last entered character had no such one-result regex match
For example with the alias regex ^(b|ba)$ the problem appears for searchstring "b" and disappears when we type the next character to search "ba"
The causeResizing the FARR window to have too small width.
The tricky thing though is that the issue doesn't appear directly after resizing. So the user will not directly see any problem with the resize. No unwanted scrollbar is shown even in case (1)(2)(3) above.
Until, that is, the FARR process is restarted. Next time FARR exits it updates the .ini with values that, on next run, will generate the problem. So a user might notice the problem only the next day after Windows has rebooted and FARR restarted.
Reproduce the problem via the GUI: Open FARR. Do a click and drag resize from the bottom right window corner and make the window very small in width (drag it to the left). Exit FARR via the tray menu. Run FARR again. The bug should now appear.
Under the hood the resize to small width makes FARR on next exit update these three keys in the .ini
MainWidth , ResultMode_Width_1 , ResultMode_Height_2
Reproduce the problem by editing FindAndRunRobot.ini Set these values while FARR is not running
MainWidth=200
ResultMode_Width_1=400
ResultMode_Height_2=200
Solve the problem by editing FindAndRunRobot.ini Set these values while FARR is not running
MainWidth=400
ResultMode_Width_1=400
ResultMode_Height_2=400
The exact numbers needed might vary depending on what skin and what visual settings the user has.
edit:These .ini variables also affect the issue.
Set them lower and the value 400 can be set lower without the problem appearing.