bug#38013: [PATCH] Rectangular region selection with mouse

[martin rudalics]

> I agree.  We need to use the same keys as in other applications:
> `C-down-mouse-1' to select the rectangular region, then move
> its current binding of `mouse-buffer-menu' to the context popup menu
> bound to `<mouse-3>' like on all other applications.

As I tried to explain before: Other applications use 'C-down-mouse-1'
for building non-contiguous regions that do _not_ necessarily form a
rectangle.

martin