Open Bug 207915 Opened 19 years ago Updated 3 years ago

position:fixed elements are incorrectly redrawn when the value of the display property changes


(Core :: Layout: Positioned, defect, P3)





(Reporter: vincent-moz, Unassigned)




(Keywords: css2, testcase)


(1 file)

User-Agent:       Mozilla/5.0 (X11; U; Linux ppc; en-US; rv:1.5a) Gecko/20030529
Build Identifier: Mozilla/5.0 (X11; U; Linux ppc; en-US; rv:1.5a) Gecko/20030529

CSS menus with position:fixed have some problems with positioning when the menu
contents disappear. Here's an example, which contains a menu with position:fixed
and a similar menu with position:absolute.

Reproducible: Always

Steps to Reproduce:
1. Open the above URL.
2. Move the mouse pointer over the first menu.
3. Move the mouse pointer upwards to make the contents disappear.

Actual Results:  
After 2, the menu flickers to the left but then it is correctly displayed. After
3, the menu is shifted to the right and the box is truncated.

Expected Results:  
One should get the same behaviour as with the second menu (position:absolute).
In fact, this is more than a display problem: When there are submenus, this bug
may render them inaccessible.
Looks like a layout problem (seeing this on Linux too).
Assignee: kmcclusk → position
Component: GFX → Layout: R & A Pos
Ever confirmed: true
Attached file test case (from uri)
Keywords: css2, testcase
This worksforme in a current build (likely as a result of widget change caching
and reflow before painting).  Vincent, are you still seeing this in current
trunk builds?
It seems to be partly fixed, but I still get a case with a strange behavior: by
replacing topleft by topright in <> and
using the CSS menu (BTW, is it possible to ask Mozilla to produce a standalone
testcase?). Opera doesn't have the positioning problem seen with Mozilla.

Note: I've tried with Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b)
Assignee: layout.r-and-a-pos → nobody
QA Contact: ian → layout.r-and-a-pos
Moving to p3 because no activity for at least 1 year(s).
See for more information
Priority: P2 → P3
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