EDIT: probably not a jEdit bug.. This is the one way I know to re-create the problem.
Environment: Gnome, Ubuntu 14.04, jEdit from the repository, OpenJDK
On occasion when performing a click, hold, and drag over selected text, jEdit will go into some mode with the mouse pointer. It turns into a no-drop sign (circle with a line through it).
EDIT: to re-create the problem, drag some text to a no-drop zone (like the line number margin or the buffer list), press ESC to cancel except keep the left-mouse drag button pressed, finally move the mouse a little more maybe 1px in the no-drop zone and see if you can get the no-drop mouse pointer to come back again. If you do, congratulations!!! your screwed (you'll probably be stuck now)... Now, fast pressing of ESC or perhaps a r-click in the no-drop zone and more fast pressing of ESC can get you out.
Another way out is to switch to a tty terminal Alt+Ctrl+F1
and locate and kill (jedit pid)
.
Any idea what this "feature" is called? It is important to know more about it, killing jedit will loose information like ones place withing files. If one does not know the tricks to get out of it, it is necessary to reset the computer.