I tried to replace one symbol in medium size spreadsheet and get freezing my Calc. I was forced to kill process of LO. Than I tried to replace that symbol in Gedit (save spreadsheet to CSV earlier) and one done it about 2 seconds. Why LO is so slow.
Maybe the reason is the dialog "Search Results"? Because in that case replacements is huge number.
*** This bug has been marked as a duplicate of bug 72413 ***