Thank you for your post.
I am able to replicate the problem. This problem only occurs with FileMaker Pro 11 running under Mac OS X 10.5.8 (Leopard). When I double-click "author" in either Mac OS X 10.6.3 or Windows XP, the entire variable name (name.author) is selected. When pasted, it pastes correctly.
I have forwarded your detailed post (Thank you) to our Development and Software Quality Assurance (Testing) departments for review and confirmation.
I can confirm this bug also affects field names in the expression editor.
Create in an expression editor window (script step, define field, etc.) a calculation that involves a related field:
Double-click on the fieldname part of the expression to select it, copy with command-c and paste with command-v.
Note the extra space before the field name.
More curious is that pasting into a text editor does not insert the space and copying from a text editor and pasting in FileMaker also does not insert the space. Only both copying and pasting within the FileMaker expression editor adds the space.
Mac OS 10.6.3