Drag Titlebar Icons to Dock or Sidebar

Sometimes, when you go to a folder via the Dock or the Sidebar or a key command, particularly if you're in list or icon view, it can be a challenge to navigate up one directory and see the folder you're currently in. Occasionally I'm in a folder, and I just want to add it to the Dock or the Sidebar, without doing any navigation, but until now, I've not known a way to do this. Today I discovered that you can add the current folder to the Dock or Sidebar by dragging the little icon at the top of the Finder titlebar (the one that represents your current folder) to the Dock or Sidebar. A silly little hint, to be sure, but maybe of some use to someone.