The current behavior in 3D Slicer for loading DICOM files have changed and automatically indexes all the DICOM files present in the same folder as the dragged DICOM file. This causes inconvenience in scenarios where a user wants to load only a specific DICOM file for inspection, especially when it resides in a folder containing multiple DICOM files.
Drag and drop usecase should just care about the dragged content and not the directory, similar to other apps in my opinion: e.g., in powerpoint, if you drag and drop an image you don’t get all the other images in that folder imported, word, and other apps too
You can make a case for when a directory is imported, but darg and drop becomes meaningless if you import all files in that folder.
Read more here DICOM drag and drop loads all the dicoms in the same folder instead of just the dragged one - #4 by alireza