70278 - [rfe] ability to undo scrolling

Status: RESOLVED INVALID

(SeaMonkey :: General, enhancement)

Description

[Jesse Ruderman]

I propose grouping scrolling actions like this for addition to the undo stack:

- Home
- End
- Groups of "left" keys:  Alt+pgdn (bug 70155), left arrow
- Groups of "right" keys: Alt+pgup (bug 70155), right arrow
- Groups of "down" keys:  pgdn, space, shift+backspace (bug 36922), down arrow
- Groups of "up" keys:    pgup, shift+space (bug 70153), backspace (bug 36922), 
up arrow
- Dragging the scrollbar once.
- Clicking to the same side of the scrollbar thumb one or more times.

Pressing a scroll key that has no effect (for example, end or down when already 
at the end of the document) wouldn't add anything to the undo list.

(Should paging be a separate action from using arrow keys?  Should timing be 
taken into consideration?)


Advantages to adding this feature:
- easier to recover from accidentally hitting home/end (which is pretty easy to 
do, since those keys are next to pgup/pgdn).

Disadvantages:
- somewhat bloaty.
- may be tricky to keep track of old positions in some documents (for example, 
if images are still loading when you start scrolling).
- not standard (afaik, the only other app that does this is the IDE Borland 
Turbo C++ for DOS, and its clone RHIDE).
- more keypresses to undo a form action if you've scrolled since then.

Comment 1

[Zach Lipton [:zach]]

Chaning the qa contact on these bugs to me. MPT will be moving to the 
owner of this component shortly. I would like to thank him for all his hard 
work as he moves roles in mozilla.org...Yada, Yada, Yada...

Comment 2

[Asa Dotzler [:asa]]

updating to new owner. sorry for the spam.

Comment 3

[Peter Trudelle]

This is pretty weird, and I've used Turbo C++.  I hope nobody is considering
this for any consumer software.

Comment 4

[Matthew T (active 1999-2002)]

Invalid. Undo and Redo should only ever navigate through editing and formatting
operations; they should not treat selection, caret position, or scroll position
as separate items (though any of these can and should change during undo and
redo, to track changes being made to the document). Similarly, undo and redo
should not record changes to zoom level, toolbar arrangement, or anything else
which does not alter the contents of the document.

The fact that it's hard to undo Home or End keypresses is a minor UI bug in the
UI standard for Windows, in that those keys move the caret as well as affecting
the scroll position. On Mac OS they scroll the document but do not move the
caret, so scrolling back to the caret position is a simple matter of pressing
any other (non-modifier) key.