PT 1.9.0.531, XP SP3:
In the Registry Cleaner - Results window:
select several rows, then press the Delete button
when you're returned to the Results window, trying to select rows "below" the ones just deleted doesn't work; clicking on them instead highlights rows further up the list.
It appears that PT doesn't correctly keep track of which rows are which after deleting some of them. I haven't been brave enough to press the Delete button after a row is mis-selected to find out which item was actually deleted -- the row I clicked on, or the row above it that got highlighted.