I am having a problem that so far I have only seen on one computer, but if one does, others might also. The issue occurs in Firefox 3 when my JavaScript code uses a div to draw a box on the screen as the user drags the mouse. As I drag the mouse and the code modifies the div's width and height, the right and bottom borders would frequently flicker and disappear. It is very noticeable.
I experimented by giving the div a silver background color and adding an inner div offset on all sides by 5px. I took a screen shot as I dragged the mouse (see attachments). I found that the inner div's right and bottom borders were at the edge of the region filled with the silver background instead of being 5 pixels within it. Therefore, it appears that Firefox is changing the size of the div, but is delayed in drawing in the newly covered area of the screen.
Maybe this is a Firefox bug, but I wanted to see if anybody had any thoughts about it. The problem only occurs in Firefox 3 (Firefox 2 works fine), and thus far, I have only seen it on one computer. In fact, I tried it in FF3 on a Virtual PC running on that same computer and it worked fine. I tried using a different FF profile to see how it worked without any add-ons loaded, but that had no effect. Any ideas what is causing this problem?
Hack, you are correct. I found another machine that had the same issue. Both of the machines with the problem run Vista 64-bit. I then created a new 64-bit VM and it too exhibited this problem. So apparently the combination of Firefox 3 and Vista 64-bit makes the issue surface (using FF2 *or* Vista 32-bit makes it go away). But which of these is the real source of the problem? I'm wondering whether I should try to design a decent test case and post a Firefox bug.
I'm wondering whether I should try to design a decent test case and post a Firefox bug.
Not a bad idea actually.
If this is happening to you then you can bet your OS it is happening to others so I wouldn't be surprised to discover that the FireFox people are already aware of it. I would be interested in hearing what they say to you in response to your test case submission. Post back when you hear something from them.