TYPO3 Core

I have implemented two table custom classes(classA and classB) for RTE and
they are working great if used one at a time. They are getting displayed in
Block Style dropdown and I can use them while editing article and the css is applied
fine in the frontend. However, I have problem when I use the two classes
simultaneously without removing the first one. ie. if I use classA and then
use classB without removing classA first, I am even unable
revert the changes without going in the Source mode and remove one of the
class. But the strange thing is if I do reverse, ie. use classB and then
classA, I could atleast remove classA and then classB using the option
Remove Block Style from the dropdown.

I am using FF 3.6.18 as browser and TYPO3 4.4.6.

TS I used is as follow:

RTE.classes {
classA {
name = LLL:fileadmin/xml/rtehtmlarea_locallang.xml:classA
value = float : left;
}
classB {
name = LLL:fileadmin/xml/rtehtmlarea_locallang.xml:classB
value = float : right;
}
}

RTE.default {
contentCSS = fileadmin/css/content.css
proc.allowedClasses (
classA, classB
)
classesTable = classA,classB
}

In content.css I have
.classA{
float : left;
}

.classB{
float : right;
}