Custom Filter Select Issue

I have created a custom filter using:

<select onClick="(arguments[0]||event).cancelBubble=true;" onChange=“gridfilter(this.value);” style=‘margin-top: 1px; width: 90%; font-family: Tahoma; font-size: 8pt;’>

When I click the drop down and go to an item the select box disappears. When I use a standard #select_filter it works just fine. The only difference I can see is that the selectfilter div tag has class “hdrcell filter” where as mine only has “hdrcell” when I change mine to hdrcell filter in debugger it appears to fix it. What is the best way to fix this? In the js files, css files, my code, etc?

Thank You,