In tab view, if I do a right-click on the tab title with the file name and select "Rename..." an input field to change the name pops up as expected.

But this renaming doesn't affect the actual file nor the entry in the list of project items, if it's stored in a project.

This seems quite confusing to me. It would be quite handy to rename files in the file-system with this function. To rename just the tab/window title only makes sense to me, if any kind of DB object is displayed within the respective tab/window.

This also relates in parts to this thread.

The rename function does indeed apply only to the window, not to any underlying file or the project items. I have added both options to the list of enhancement requests.