Cygwin: problem with renaming and case

Hi, Don't know exactly if this is a bug or a feature or something in the middle, but I have a lot of problems while changing just the casing of file names and using git mv und cygwin. Here's a test case:

mkdir testrename cd testrename git init echo "AAA" >aaa.txt echo "BBB" >bbb.txt git add aaa.txt git add bbb.txt git commit -m "First commit" git checkout -b new_branch git mv aaa.txt ccc.txt git commit -a -m "Moved file" echo "NEW AAA" >Aaa.txt git add Aaa.txt git commit -m "Added Aaa" #aaa.txt exists in master, Aaa.txt in new_branch git checkout master

Last command gives: "fatal: Untracked working tree file 'aaa.txt' would be overwritten by merge". I know I can use git checkout -f but the problem returns while others do merging/pulling from my repo, etc. Thanks, Frank