It's slow when generating the tree for a directory with a amount of files, you need to wait for a while in this case.
The .gitignore file in the subfolder will not be parsed. So you might find the patterns of the .gitignore file don't work if you used .gitignore in the subfolders.
When there is a folder ignored by .gitignore, it's possible to wrongly ignore all the files which is under the folder althought some files should not be ignored. For example, when folder test is ignored by .gitignore, the subfile test.md is possible to be ignored althought there is also a line !test.md in the .gitignore file.