OK, this may be a rather obscure problem, but I've noticed it in the betas of Sierra, but it unfortunately carried over to the final release. I deal with a lot of images for work, and when modifying and saving images in Photoshop, I will often click on the filename of the "base" image when saving to modify it slightly. So if had a base filename of Radeon_Fury, I would simply click on the name of the original file in the save dialog box and the field would automatically populate with Radeon_Fury and I could then change it to Radeon_Fury_2 or small_Radeon_Fury with ease. Now, when clicking on an existing file from the dialog box, it does nothing. So I have to go through and retype the filename each time I want to save a slightly different image (or other document) which is a time waster. Same problem occurs in other apps like Word or anything that allows you to save a file. Is there a way to change this behavior?