“Open File in BBEdit” missing from right click menu

You can do this on the Macbook Pro trackpad by pressing down with two fingers hard enough to engage the mechanical "mouse" button built in to the trackpad. Drag your item(s) to the desired destination and then release the pressure off the button and... voila! Windows will display the right drag menu at that point.

Unfortunately this doesn't allow "locked drags" where you can continue dragging long distances by picking your fingers up off the trackpad surface and quickly repositioning them to continue the drag.

From your question it looks like your Dropbox is misbehaving.

Do you have the latest version of Dropbox? Reinstall Dropbox with the newest version.

Dropbox uses a "hack" which extends the Finder (in an unsupported way) to provide this "sharing" link. Because these "hacks" can cause crashes, Apple tends to disable them when newer versions of OS X ship. There's probably a newer version of DropBox that gets around these restrictions that you'll need to download.

^{Source: https://discussions.apple.com/thread/5577081}