When saving a document or editing a file name, with the focus on the string itself, why does CMD+Delete move the file or folder to the trash? To be more specific, I am saving a file from my markdown editor. Within the save dialog box, I navigate to the folder I wish to save the file. I then decide to change the name of the file. I put my cursor at the end of the text string and hit CMD + Delete. The expected behavior is to delete the entire string. Instead, this deletes the previously selected folder I highlighted in the dialog box. 

Typically, I expect CMD + Delete to remove an entire line of text. I also tested this with renaming a file. If my focus is on the string name of the file, why would CMD+delete remove the file, when Option+Delete removes individual words as expected. 

I can do screen shots or short movie if this is confusing. I don't recall this happening previously but I'm not often creating files outside of Python.

13" rMBP using 10.10.1
If the file name is highlighted then just use Delete, not the CMD+Delete.

The CMD+Delete will also delete the file on my MBA with 10.9.5 Finder.