The COLOR style attribute is removed from the contents after switching to HTML editing mode (in Firefox)

The color format in firefox don't work anymore and completely destroy all the previous formatting when a user edit it.

Steps to Reproduce:

I have a treelist and inside the editform a htmleditor with a a custom button that insert a text like the following

"<span style="COLOR: red"><strong>hello world</strong></span>"

the step are

 - edit a node;

 - press the custom button

 - the text with red color appear

 - switch to html view and then back to design mode and you will see that the format had been erased and became like this -->

   <span><strong>hello world</strong></span>

You get the same behaviour if you edit, press the custom button than save. the format go crazy

With IE7 no problem at all.

I also noticed that with frefox if you write a text than select it and change the color to red, you get: <span style="color: rgb(255, 0, 0);"><strong>hello world</strong></span>

while in ie7 you get: <span style="color: #ff0000"><strong>hello world</strong></span>