Summary: Let the user drag-n-drop targets in "Target in document" window to
compose a link.

Notes: 
* This issue builds on Issue 60640. 
* It also solves the problem hiighlighted in  Issue 60635.

The scenario is as follows, assuming that the "Target in document" window is the
primary window for creating hyperlinks (ref:Issue 60640). 

Further suggestions:
1. Make this window modeless, so that the user can leave the window open as he
browses across the document to create any number of links.

2. Once the user highlights a text, let him use the Navigator to select his
target. Let him select an entry from the Navigator and drag-n-drop it into the
"Target in document" window. 

This way, there is no need to refresh the window (ref:  Issue 60635), as the
Navigator is already refreshed to reflect any changes in bookmarks, headings, etc..

3. User presses the "Apply" button. This completes the creation of a hyperlink.

4. The user repeats steps 1-3 for other hyperlinks.

5. Finally, user closes the window.