Ctrl+Z undoes too much, and the result is no more undone what you originally wrote, but the shortcut key for recovery is: Ctrl+Shift+Z;
1. Ctrl+z is the undo shortcut key
2. If you want to restore the content dropped by Ctrl+z, press the shortcut key: Ctrl + Shift + Z.
If Ctrl + Shift + Z does not work, it is a shortcut key conflict. Resolve:,
File-->Settings-->KeymapSearch redo, you can modify the shortcut key to return to undo.
[I set Ctrl + Y]