I messed around this forum a lot but couldn 't find anyone with this kind of problem.
When I want to drag and drop a file into a sub-sub-sub folder, I used to
1) drag the file
2) move it over a folder (without releasing it)
3) after 1-2 seconds, the folder would open, revealing its sub-folders
4) drop it into a sub-folder.
What happens now is that, without changing anythin to my mac, step 3 doesn 't occur at all. I always have to drop a file in a folder, then drag it from the folder and drop it into a sub-folder etc etc.
Is there any logical explanation to this?
I am using OS X Lion 10.7.5
Choose Preferences from the Finder menu, click on the General tab, and check the box for spring-loaded folders.