I really, really like the new MTP support in DO 10.5.0,0. Something that's been wicked lacking in available phone apps and PC file managers.
One glitch, however. When in Tree view, clicking on a folder within the tree does not open that folder or display the sub folder tree. Instead, you must double-click on the folder you want to open in the file panel, not the tree panel. That folder then opens. To drill down further, you must double-click on each subfolder in the file panel as you work your way down.
Not a big problem, but one that would be nice to correct. This glitch may be limited to my systems. The Desktop i"m using is still running XP SP3, and the MTP device is a Samsung Galaxy S3 running Android Jelly Bean.
Otherwise, I can open files on my MTP device normally, just as I can any other file displayed in any other drive in DO. Folders of images open automatically in thumbnail view. A very well worked out feature.
On the Galaxy S3 I'm using the ES File Explorer app, which allows me to fully access my desktop system via my wireless network. Doesn't allow me to access the cell phone from my PC, though. Just access the PC from my cell phone. I was kinda hoping that the new MTP support would allow DO to recognize my device on the wireless network so that I could go untethered, but I guess that would take a lot more doing.