My ability to dragon and drop files into InDesign has stopped. I also cannot copy and paste. I have tried dropping previously used jpg's and PDFs as well as copying text from Acrobat, Chrome and Word. I reset the prefrences with control option command shift, but still no luck - I can't drag and drop files. Also, I cannot move files with my mouse in the program.
Nobody can help you without system information. Could be anything from graphics driver issues to a defective mouse to a busted operating system...
Moved from the Creative Cloud to the InDesign forum. They will be able to help you here.
Could be the mouse. Have you tried a second one to see?
Does it work in a different user?