How to Drag and Drop files to open application?

Encouraging update (Nov 2020) after waiting since 2012 (!), see also github-comment from 2015:
vadikom presented an approach to get it working with the GNOME extension Dash-to-Dock (tested on Ubuntu 20.04 and Pop!_OS). Please test it and comment!

If you would like to test it:

1. Find and backup the following file: ~/.local/share/gnome-shell/extensions/[email protected]/dash.js
2. Make a copy of the file dash.js
3. Open the file dash.js with a text editor and replace the content with the text from the Github User Content.
4. Hit alt + F2, type r and hit Enter to reload GNOME shell.

For some known issues and thoughts see vadikom's post.
Source code on the fork of Dash-to-Dock.
A short video about how it looks like.

Apart from that there are two ways of one inconvenient possibility (see comment below):

• Left-click on the file, hold it, press the keys alt and press as many times the key tab to navigate to the window you want to drag the file to (while still holding the left-click), release alt when the right application window is chosen and drag the file to the desired place to drop. (This is difficult on a laptop while using the touch pad, though, easier with a mouse.)
• If you click on alt & tab and hold alt (as well as the left-click on the file, the overview of all opened windows/apps will open and you can move the cursor over the appropriate window and finally release the file there when the windows is opened (Thanks fcole90).
  With Nautilus, it looks like this only works if the files are in list view not icon view!

For some it works without the keyboard, but just the mouse or touchpad or whatever you use to move your cursor. You drag the element to the bar, this triggers the overview window, you then drag the item to the window you want, then the window get focus, finally release your item.

Kyriakos Loizou suggests the same behaviour but with left-click on the file [I have to drag the file to the Dash to Dock] and then click & hold the super (while still holding the left-click). This triggers the overview window, you then drag the item to the window you want, then the window get focus, finally release your item.

There is also a bugzilla-report. Maybe we can all subscribe to this bugzilla-thread and the github-thread to show the support for it and please contribute or comment** with your reaction (smiley, thumb up, ...). I think this feature is crucial for Ubuntu and without it a real pain.

What you might be trying is to drag the file to the application shortcut. This feature is not available in Ubuntu 18.04 as far as I know.

A simple and better trick:

• Step#1: Click and drag the file just to hold it.
• Step#2: Press Alt+Tab on your keyboard and keep pressing the Tab until you reach the desired window where you want to drop.
• Step#3: When you see your the window where you want to drop, just release the file.

You can try the following command in your terminal. It worked for me on ubuntu 18.04.

gsettings set org.gnome.nautilus.preferences use-experimental-views false

As of today, I have noticed that you can now select a file with Left-click and while holding the mouse button down you can then press the super button on the keyboard. This will preview all running applications or open folder. Then, while you're still holding the mouse button down, move the mouse over the application/folder you would like to move/add it to, hover over it for 2-3 seconds and it will become focused, now you can drop the file there and it should be added.

I have tested this behaviour with an image file dropping it into Inkscape and works like a charm. I'm not sure how effective this is with other applications, but I don't see a reason why it shouldn't work.