[Lazarus] Procedure List dialog regressions

[Juha Manninen]

I reverted r50908 in r51748. I think only that one revision was involved.
I planned to work on the issue sooner but something else always came up.
It is also true I don't fully understand the original filter logic. I
must study it later.
Currently I am travelling with a mini-laptop and won't do real development now.

Graeme, do you know how to fix the other regressions that happened
sometime earlier, like the missing icon thing? Patches are welcome.

Juha