The file is still open in Shared mode, and so cannot be edited until you switch to Exclusive mode; although, you will only be able to enter Exclusive mode if no other user has the file open (in either Shared or Exclusive mode).
The file lock status now changes to Exclusive, and the icon in the File group changes to (Switch to Shared Mode).
Notice how the record is using the default layout, because the first field is not set to 'M' or 'E' (either of which would result in a conditional layout being used).