I had also tried updating to 11.2 when it was released and had problems with that too. I’m not having much luck lol.
11.2 for some reason failed on recognizing my SATA raid even though during config it identified and I could format to ext4. On first boot however, the file system check would not recognize it and failed, even as an ext3 like it was originally. I went back to 11.1.
Kde 4.4 Dolphin works fine on my 11.2 system, no problems deleting files or anything, and viewing folders with lots of files in them doesn’t slow it down either.
I’d say it’s probably the 11.1 you’re still having.