Have been working for a day on getting the "manage attachment" popup to work perfectly as a Bootstrap modal; but I cannot get it to work perfectly 100% as a modal, so I have modified the popup to look like a modal, but it is really just a page popup for now:
This works for "new reply" and "edit post" and "advanced editor" but does not work (yet) in the quick reply editor (QRE).
However, it is much better than before, not perfect as modal or working in QRE yet, but drag and drop from the desktop works well.
A bit bored with this for now; I will move on to another modal, perhaps the color picker or smilie picker, or maybe something else.
Have a great weekend!