To reproduce:
1. Set sorting mode to Name.
2. Select a file in the browser, and Ctrl-Drag it to a new position in the folder
Results:
1.11.5: Sort mode is changed to Custom, and existing file is rearranged into new sort order
1.11.4 and previous versions: File is copied, sort mode remains unchanged
Ctrl-Drag in the same folder must COPY the file, not change the sort order, to agree with convention and previous versions.