221941 - "File Types" listbox in "Helper Apps" prefs dialog does not scroll when it contains 10 items

Status: RESOLVED DUPLICATE of bug 143663

(SeaMonkey :: Preferences, defect)

Description

[David Costanzo]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20030925
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20030925

Under Edit->Preferences, Navigator->Helper Apps, there's a dialog box with a
list of "File Types".  The vertical scrolling on this list box is messed up when
there are exactly 10 items.  The symptoms are that you can't scroll down to the
last item in the list box using the mouse.  Dragging the scrollbar will move the
scroll location, but does not scroll the items in the list box.  Clicking on the
down arrow box at the bottom of the scrollbar has no effect.  You can "scroll"
to the last item using the down arrow on the keyboard, but you can't see what
you've selected.

When you add an extra helper app (for a total of 11 file types), the scrolling
works as expected.  When you remove one item (for a total of 9 file types), all
items fit inside the box and no scrollbar is shown, as expected.  The problem
only shows itself when there are exactly 10 file types.

10 registered file types is the magic number for my setup.  This value may be
dependent on my monitor resolution, font size, etc.  For the sake of a repro, I
suggest using exactly as many file types as it takes to make the vertical
scrollbar appear.


Reproducible: Always

Steps to Reproduce:
1.Select Edit->Preferences
2.Select Navigator->Helper Applications
3.Make sure they are exactly 10 items in the "File Types" list box by either
adding or removing items.
4.Try to click and drag the scrollbar downward to see that last item.

Actual Results:  
The scrollbar correctly goes down to the bottom, but the items in the listbox do
not scroll downward.

Expected Results:  
The items in the listbox should be scrolled downward, so that the last item is
visible.

My copy of Mozilla started off with 10 registered file types, so this should be
a common problem.  In fact, I expected this to have already been reported, but I
didn't see any existing bug report that looked like this one, although #143466
came close.

Comment 1

[Jan Kozanek]

This is a dupe of Bug 143663

Comment 2

[Christian :Biesinger (don't email me, ping me on IRC)]

*** This bug has been marked as a duplicate of 143663 ***