I see the same on the page.
It is caused by a problem with the code and a missing clear: both CSS rule for the table with the search results.

This code in Stylish should fix it:

@-moz-document domain(www.sigmaaldrich.com){
 #moreErrorMsgBox+table {clear:both}
}

thanks a lot corel for your quick answer. However, in internet it looks fine. I think the part has shifted to right with making a white space in between. it must be a problem with firefox only. I remember in some old firefox it was completely ok. anyway thanks for your time. i should try it.

IE always tries to guess what the code is meant to do and if there is a problem then you won't notice if you only test the code in IE. Firefox requires a clear rule to make the content start below floating or absolutely positioned containers, otherwise the content is positioned to the right of those, in this case hidden, DIV containers, and content shifts to the right as happens here.

wow....corel......it is really great. now it is corrected. frankly, I am dying to know what you did. actually I dont understand how did you know which is Errormsgbox and which is Table so that you can clear both. i really want to apply your knowledge to other websites where i had similar problem. or the better, can you tell me the javacode to do so in greasemonkey. then i can do research further to correct in all websites. anyway, salute to you again.

Hurray............i got the answer for anybody still having the problem. I just installed NOSQUINT and all problem gone. A great help. Though stylish was also ok, but i did not want to use this addon only for 1 page.