Netscape 7 was squashing some table cells down, ignoring widths I had specified in the css.

The code for the table:
<table id="learningPlanTabsTable" cellspacing="0"> <tr Height='25px'> <td class="action" nowrap valign="bottom">   <!--selected tab title--> <strong>Summary</strong>   </td> <td class="action" nowrap valign="bottom">   <!--unselected tab--> <a href="link.htm">Plan Details</a>   </td> <td class="action" nowrap valign="bottom">   <!--unselected tab--> <a href="link.htm">Certifications</a>   </td> <td class="action" nowrap valign="bottom">   <!--unselected tab--> <a href="link.htm">Transcript</a>   </td> <td colspan='100%' align='right' width='100%'><Input type='button' value='Print Report' onclick='printPage();'></td> </tr></table>

Without the style

table-layout:fixed;

#learningPlanTabsTable {
width:100%;
}

#learningPlanTabsTable td.action {
	width:136px;
	height:25px;
	background-image: url(images/tabs/deselected/tab_01.gif);
	background-repeat: no-repeat;
	margin:0px;
	font-family:Trebuchet MS, Helvetica, Arial, sans-serif;
	font-size:13px;
	background-color:;
}

View image

With table-layout:fixed;

#learningPlanTabsTable {
/*table-layout:fixed is necessary to keep mozilla browsers from squashing the tab cells*/
table-layout:fixed;
width:100%;
}

#learningPlanTabsTable td.action {
	width:136px;
	height:25px;
	background-image: url(images/tabs/deselected/tab_01.gif);
	background-repeat: no-repeat;
	margin:0px;
	font-family:Trebuchet MS, Helvetica, Arial, sans-serif;
	font-size:13px;
	background-color:;
}

View image

Thanks much to Quirksmode for the tip.