Thank you very much for considering the feature.
I have to say that I'm quite amazed at how deep the feature set is, especially the ability to customize the app so uniquely for each user. To be able to layout my own views is priceless. I love having access to everything I typically do with a song on one screen that I'm also able to layout precisely based on the way I work.
While I don't want to push my luck asking for too much, the only other thing I find a little cumbersome is having to jump completely out of my show view/custom layout of a song to be able to utilize the Open In feature. While in my custom view of a specific song, I find I often need to edit a recording, video (I slow down videos in other apps), or other document using another app. Maybe when clicking the multiple document button or multiple recording button, when you display the popup to choose the document/video/recording, if you press and hold the specific item for a moment, the Open In option could appear. That would feel intuitive for me at least. As it stands now, I need to exit my song, navigate all the way back to documents or recordings, and then figure out which item I need to Open In from a huge list of entries. I just figured I'd offer up maybe a simpler way of doing this.