The original bug report can be read here:
The identity test with string compare (ie.
source==target) is invalid on case-insensitive file
sytems. On the worst case, this leads to data loss when
renaming a file "test" in "Test" on eg. a vfat file system.
The attached patch uses FXFile::identical() which also
compares inodes. The patch is against 0.72, but should
apply to 0.80 where the bug is also present.