301478 - Scrollbar draws outside of content area

Status: RESOLVED FIXED

(Core Graveyard :: Widget: Mac, defect)

Description

[jhp (no longer active)]

To reproduce:

1) Open https://bugzilla.mozilla.org/attachment.cgi?id=189081&action=edit.
2) Scroll the page down so that the frame in the upper right that contains the
attachment text is only partially visible.
3) Click in "Comment" textarea in the lower left.
4) Now, drag scrollbar thumb of attachment frame.  You should see scrollbar draw
over the toolbar and tab bar.

I just updated to the very latest checkins in widget/src/mac.  I don't know if
any of the patches in other bugs that have yet to be checked in will fix this,
so I wanted to open this bug to see if it is a new issue or not.

Comment 1

[Simon Fraser [no longer active]]

Yes, I can reproduce. It's the caret messing with the port again  :(
Maybe we do need that carbon event handler after all.

Comment 2

[Mark Mentovai]

It's the clipping this time, I guess.

Comment 3

[Mark Mentovai]

If we toss the draw event handler back in and do this:

  if(wasDrawing=mDrawing)
    EndDraw();
  StartDraw();
  ::CallNextEventHandler();
  if(!wasDrawing)
    EndDraw();

then the world is happy, except that the moment we install the draw event
handler, even if it does nothing, we experience bug 300058.

Comment 4

[Mark Mentovai]

I'm seeing (in the draw event handler) weird clipping region bounding rects
during scrollbar draws in a few cases: when scrolling an iframe, and when the
caret is going.  I don't know where these clips are coming from, because I've
set prints at every SetClip and ClipRect I found in mozilla, and nothing
corresponds to the weird regions I'm seeing.

Most of the weird clipping regions are sort of harmless, 1px wide or high
instead of 15.  The regions that are causing this bug are completely bogus.  For
example, when expecting bounding (t,l,b,r)=(73,0,385,15), I see (11,0,579,39)
with the most recent SetClip call having been in SetupPortState and bounded by
(0,0,579,614) (which would suck too).

Comment 5

[Wayne Woods]

If I click on a link and then start playing with the vertical scrollbar before
the page starts reloading, sometimes a scrollbar artefact draws over the
toolbar, but not in the same place the test case for this bug. It draws up in
the top, left corner, the same as in bug 298677. Unfortunately I can't reproduce
it all the time. Still trying to find conditions that will do that.

However, would that be something to report here, or should I open a new bug
about it?

cheers

Comment 6

[Mark Mentovai]

Different bug.  This one's a clipping problem, you're seeing an origin problem.
 The draw event handler would solve both, at the cost of bug 300058.

Comment 7

[Wayne Woods]

Thanks Mark. FYI, I finally found a couple of pages where I can reproduce my bug
frequently, and opened it as bug 304607.

Comment 8

[Mark Mentovai]

See attachment 193249 [details] [diff] [review] to bug 304607 for the infamous event handler.

Comment 9

[Mark Mentovai]

This is fixed (trunk) by bug 311399.