CSS for multiple <div> in IE 9 has no effect

Grid 3.5. Internet Explorer 9.

Embeded multiple

in a cell. Such as:
AAA
BBB
CCC
DDD

The CSS used:

.panel1{
float:left;
padding-right:10px;
}
.panel2 {
float:left;
width:40%;
}

.panel3{
float:left;
width:25%;
}

.panel4{
float:left;
width:20%;
}

This worked fine for FireFox and IE 8. The display is:

AAA BBB CCC DDD

But it failed the IE9. For IE9, the display became:

AAA
BBB
CCC
DDD

My question is:

How to fix this issue on IE9?

Thanks

Scott

To add more information for this issue. I further found that the IE9 has some difficulty to recognize the class attribute. For example, if I put the style directly in the

tag, it would work. Such as:
AAA
BBB
CCC
DDD

But if I put use the css class, instead, it will not work, i.e.,

AAA
, etc.

How come the IE9 can not recognize the class attribute inside the cell? Is there any solid solution for this problem?

Thanks

Scott

Unfortunately the issue cannot be reproduced locally.
css class works well for us in IE9.
If the issue still occurs for you, please, provide with a complete demo, where the issue can be reproduced locally.