bug#16149: 24.3.50; rectangle-mark-mode: Tabs + Inability to C-x r o a rect. of width 4

[Stefan Monnier]

> In the attached screenshot, I am trying to C-x r o a rect. of width 4.
> The intention is to indent the whole snippet to column 4.
> Now, if you move the cursor vertically down (and subsequently in the
> horizontal direction), you will note that the highlighted region
> "forcibly" becomes zero width or of 8 chars.

Not sure what this has to do with rectangle-mark-mode.  The same holds
in all Emacs versions so far.

> I can in no way rest the cursor at col. 4 (on a row that has the tabs)

Sure you can: C-a C-x C-x C-4 C-f.

But, yes, this is a limitation that is difficult to fix in the old
rectangle UI whereas the rectangle-mark-mode offers the possibility to
fix it more easily, at least from the UI point of view.
The implementation is still missing (tho cua-rect.el provides the
feature already).


        Stefan