21243 - GFX scrollbar slider insensitive to perp cursor positioning

Status: VERIFIED DUPLICATE of bug 22175

(Core :: XUL, defect, P3)

Description

[Sean Richardson]

* Overview:
Testing bug 7408 "[PP] scrollbar thumb too sensitive about cursor positioning"
with a current Windows NT binary with GFX scrollbars enabled, it was impossible
to move the cursor to a position where the scrollbar slider was no longer
active and the view and slider snapped back.

* Steps to Reproduce:
0. Ensure that GFX scrollbars are enabled.
1. View any page that is too long to fit in the browser window and
   has an absolute width so both vert. and horiz. scrollbars will appear -
   this bug report page will do if the window is narrowed to ~ 600 px wide.
2. Play with both scrollbars: click on the slider, hold down the primary
   mouse button, move it in the direction of the scrollbar, then move the
   mouse pointer into the canvas area and move it in all directions.

* Actual Results:
For all of the bug 7408 testcases, and for other pages, once the GFX scrollbar
slider has been moved at all, it is possible to move the mouse pointer
perpendicularly to the scrollbar hundreds of pixels into the browser
canvas area and still have motion in the direction of the scrollbar
move the slider, even if the mouse pointer leaves the window entirely at
times, so long as the primary mouse button is held down throughout.
This happens for both vertical and horizontal scrollbars.

* Expected Results:
Much like Navigator 4.7: the slider will still be active and work with
parallel motion of the mouse pointer so long as the pointer stays within
~ 25 px of the scrollbar perpendicularly, but the slider and view will
snap back if the pointer moves further away perpendicularly.

* Tested with:
1999-12-08-08-M12 nightly binary on Windows NT 4.0sp3, with GFX scrollbars on.

* Additional Information:
Leaving the scrollbar is still too sensitive with native scrollbars in WinNT
(see bug 7408, tested with same binary), but if GFX scrollbars will be the
shipping scrollbars, this is surely the bug to fix.

[PP] status unknown for this bug with GFX scrollbars enabled.

Comment 1

[Sean Richardson]

Is the correct Component "XP Toolkit/Widgets" or "Event Handling"?
Trying "XP Toolkit/Widgets" in case that is the correct component.

Comment 2

[Peter Trudelle]

I actually prefer this behavior to the narrow tolerances on Win32, but you are
right that expected behavior is for the thumb to snap back, at least on Win32
and MacOS, but the amount of leeway varies considerably by platform.  I think
the Mac is much more forgiving in this regard, around 125 px, yet still quite
easy to snap back when you want to.  Current behavior is customary on Linux.
Assigning to evaughan, cc german.
BTW, this is an extremely well-written bug report, thanks!

Comment 3

[Peter Trudelle]

targetting p3 for m14

Comment 4

[Claudius Gayle]

stealing this bug for me. janc, I'll take any other gfx-scrollbar bugs you come across as well. (from a QA standpoint of course)

Comment 5

[Eric Vaughan]

This is not how the netscape look and feel scrollbars work. The snap back
behavior is just on way in which scrollbars can be implemented. Remember we are
not doing the windows look and feel we are doing a X platform look and feel. In
the future scrollbars behaviors will be defined in the chrome and you will be
able to have a skin with this behavior. But that is down the line. So I will
treat this bug as a feature request.

Comment 6

[Sean Richardson]

OK, I understand the rationale for having one type of scrollbar behaviour, XP,
and I will understand if this has been specified and locked down, but is the
X style of scrollbar really what is wanted? While it is pleasant to not have
the scrolling position snap back unexpectedly, there are times when being able
to return to the originating position without scrolling back can be very useful,
especially with long documents, where it can be difficult or tedious to find
that spot again.

In particular, what rationale is there for having the scrolling continue when
the pointer is well outside the window? If X is set to move focus on mouseover
rather than on click, a buffer zone of 30 to 100 px outside the window would be
wanted to avoid losing focus, but by making it impossible to snap back the
scrolling position at all, a feature used by Windows and Mac users is taken
away.

I can see the point of having a distinctive UI, XP, so how about this:
having the scrollbars act as they are inside the window, but snap back if
the cursor strays more than 60px *outside* the window, in any direction.
That would preserve much the same feel without taking away a feature entirely
from Mac and Win, while adding a feature on X.

Comment 7

[Sean Richardson]

Marking as a DUP of bug 22175; exact same issue: sometimes being able to jump 
back to where the scrolling began is useful, especially with very long pages.

*** This bug has been marked as a duplicate of 22175 ***

Comment 8

[Claudius Gayle]

VERIFIED Dupe