This is not related to Indesign or Adobe tools, because the are opened by the file system of your OS. You better ask at a Mac forum, unless you find a way to set Command-Arrow down to open your INDD.
I'll definitely ask at a Mac forum as well, though the Command-down arrow does work as it should in the Finder (as well as other apps, internet, adobe, etc) and it does work properly in InDesign except for that last "Open file" command. Apple lists "Command-Down" as being the keyboard shortcut for "Open highlighted file" so I'm wondering if there is some sort of conflict at play here, though I can't find one.
This morning, I checked on my wife's computer, and it's reproduceable. Command-Down works except for opening a file from inside of InDesign (or placing a file). She's running CS6, on Mavericks (not sure what exact version).
So I'm lead to believe this is inherent to only InDesign, and only CS6. Can anyone else reproduce this? (Perhaps it's simply an existing issue with CS6.) If it's simply how InDesign CS6 behaves and everyone has the same result, I could live with that; after all, Enter and Command-O will still work. I'm just trying to isolate the cause, be it InDesign or OSX. If I CAN fix it, I would love to, because I use that shortcut all day long at work and while it does only save a fraction of a second, it does add up over the week, not to mention muscle memory confuses the heck out of me when I get home and suddenly files stop opening for me.
It's like losing a pencil... insignificant and easily worked around, but I hate not knowing. Whether it be where my missing pencil is or why a key shortcut behaves strangely. Thanks!
Silly situation. The Finder window that open from inside Indesign to select an INDD is still a Finder windows. I can't imagine that Indesign can incfluence keyboard shortcuts for this window.
However, there are other ways to open a file, like drag 'n drop. No option?