SourceTree / git add-无法暂存修改的文件

Question

I use SourceTree daily and never had such issue. But today I did some minor change and now I ended up having this issue:

What I changed today?

I added p4Merge as merge tool and diff tool in my git config. Then I changed my mind and deleted entries for p4Merge from my /.gitconfig file since I noticed I ended up having double entries for merge and diff tools there.

Here is how that looked

However, after removing all entries for p4Merge tool, I noticed that I am unable to stage files from SourceTree anymore. Below screenshot shows that I have 4 upstaged files. If I try to stage them by checking off the checkbox beside them, nothing will happen. The wont be moved to Staged files section

UPDATE

Using git add . also does nothing and I notice that terminal shows files as modified but they are not red nor green but purple:

Answer 1

In order to fix this issue, I renamed one of the files above.

Next I issued git status and that saw the original file as deleted and new file with new name added

git add . worked this time and I added file

Then I issued git commit -m "message" to commit change

Then I changed name back and did git add . / git commit -m "message" git add . / git commit -m "message" again and that fixed all files, not only the one I renamed.