[FIXED-1310] Slow css :hover behavior on IE7 with large datatable

[littlealan]

Slow browser response when scrolling a large table with about 300 rows on IE7. It is because there is a :hover css class defined on a non-anchor (<a>) element. Removed it solved the problem. No problem for FF and Chrome.

e.g. in the attached sample html, the below class will make the page scrolling very slow, even no DOM element applied this class.

<style type="text/css"> 
.foo.bar:hover { 
        BACKGROUND-COLOR: #0000FF 
    } 
</style>

Searched the css in ext-all.css of 3.1.1 and 3.2.1, below class caused the problem. Comment out this class solves the problem:
.x-color-palette em:hover, .x-color-palette span:hover

Please fix the above mentioned classes.

Reference:
http://west-wind.com/weblog/posts/354547.aspx

Cannot attach the sample file. Please download here:

https://docs.google.com/leaf?id=0ByF...thkey=CIeB7dUE

[Condor]

Just tested and this really makes a huge difference on IE7!

trackMouseOver:true goes from 'completely unusable' to 'really slow' (comparable to IE6 and IE8).

[Jamie Avins]

Thank you for the report, I know I've seen this one before but mixed it up with opacity.