Please try that with 4.0.2.
im using version 4.0.0(build 342).
the problem is when opening some files (in this case a .txt) with a big length(not big size) the Internal Text Editor seams to not read all content. to verify if i was correct first i reload the file but he didnt show the content was missing, then i open a shell and saw the rest of content that Internal Text Editor not show by typing tail file.txt and after that i realized that content was missing.
and sometimes , in the past(i dont know which version) when copying a big amount of files from the remote machine to local machine the winscp freeze. probably this version does the same.
sorry for the english.
thanks