219182 - Menus and submenus are very sluggish and submenus collapse if cursor is moved quickly

Status: RESOLVED DUPLICATE of bug 183147

(Firefox :: Menus, defect)

Description

[Malcolm Coupland]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.5a) Gecko/20030728 Mozilla Firebird/0.6.1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.5a) Gecko/20030728 Mozilla Firebird/0.6.1

It is necessary to hover the mouse for a second or two before submenus appear
(e.g. in Bookmarks) and then when moving towrads target item very careful
navigation is required in order that the submenu does not collapse, i.e. you
must first move exactly horizontally, then wait for new selection highlight,
then move virtically.  Often pointed-to item does not immediately select,
requiring up and down dithering.  This all slows down browsing enormously.  C.f
IE6 where you can move the cursor right outside the menu tree and the tree does
not collapse.  Maybe only a problem for slowish CPUs (mine is 400MHz)?

Reproducible: Always

Steps to Reproduce:
1. Use an old computer without super-fast CPU
2. Have well-populated Bookmarks with deep submenu tree.
3. Try to select Bokmark deep in submenu tree, moving the cursor diagonally
through the submenus.

Actual Results:  
The submenu tree collapses back to the parent menu

Expected Results:  
Submenu tree should stay open until mouse is clicked.  Submenus should appear
much more promptly.

I use the default theme.  I have tried playing with the submenu response time
using TweakUI for Windows XP but it is only by setting this very slow that I can
defeat the collapse problem, and then the submenu opening time is unusably slow.
 I cannot obtain a satisfactorily quick submenu opening time, even on the
"instant" setting.

Comment 1

[Simon Paquet [:sipaq]]

*** This bug has been marked as a duplicate of 183147 ***

Comment 2

[Malcolm Coupland]

Not quite a duplicate of 18147 since THIS bug report mentions the sluggishness 
of submenu opening, need to dither the mouse, etc.