diff --git a/html/cgi-bin/zoneconf.cgi b/html/cgi-bin/zoneconf.cgi
index d99a3e611..2501901c4 100644
--- a/html/cgi-bin/zoneconf.cgi
+++ b/html/cgi-bin/zoneconf.cgi
@@ -26,7 +26,7 @@ require '/var/ipfire/general-functions.pl';
 require "${General::swroot}/lang.pl";
 require "${General::swroot}/header.pl";
 
-my $css = <<END
+my $extraHead = <<END
 <style>
 	table {
 		width: 100%;
@@ -64,19 +64,19 @@ my $css = <<END
 	}
 
 	td.green {
-		background-color: $Header::colourgreen;
+		background-color: $Header::colourgreen !important;
 	}
 
 	td.red {
-		background-color: $Header::colourred;
+		background-color: $Header::colourred !important;
 	}
 
 	td.blue {
-		background-color: $Header::colourblue;
+		background-color: $Header::colourblue !important;
 	}
 
 	td.orange {
-		background-color: $Header::colourorange;
+		background-color: $Header::colourorange !important;
 	}
 
 	td.topleft {
@@ -112,6 +112,44 @@ my $css = <<END
 		margin-top: 1em;
 	}
 </style>
+
+<script type="text/javascript">
+	//highlight interface access selection, call this from "onchange" event of selection element
+	function highlightAccess(selectObj) {
+		if(!(selectObj && ('zone' in selectObj.dataset) && ('mac' in selectObj.dataset))) {
+			return; //required parameters are missing
+		}
+
+		var zoneColor = selectObj.dataset.zone.trim().toLowerCase(); //zone color (red/green/blue/orange) CSS class
+
+		function colorParentCell(obj, color, enabled = true) { //find nearest parent table cell of "obj" and set its CSS color class
+			do {
+				obj = obj.parentElement;
+			} while(obj && (obj.nodeName.toUpperCase() !== 'TD'));
+			if(obj && (['green', 'red', 'orange', 'blue'].includes(color))) {
+				obj.classList.toggle(color, enabled);
+			}
+		}
+
+		//handle other associated input fields
+		if(selectObj.type.toUpperCase() === 'RADIO') { //this is a radio button group: clear all highlights
+			let radios = document.getElementsByName(selectObj.name);
+			radios.forEach(function(button) {
+				if(button.nodeName.toUpperCase() === 'INPUT') { //make sure the found element is a button
+					colorParentCell(button, zoneColor, false); //remove css
+				}
+			});
+		} else { //this is a dropdown menu: enable/disable additional VLAN tag input box
+			let tagInput = document.getElementById('TAG ' + selectObj.dataset.zone + ' ' + selectObj.dataset.mac); //tag input element selector
+			if(tagInput) {
+				tagInput.disabled = (selectObj.value !== 'VLAN'); //enable tag input if VLAN mode selected
+			}
+		}
+
+		//if interface is assigned, highlight table cell in zone color
+		colorParentCell(selectObj, zoneColor, (selectObj.value !== 'NONE'));
+	}
+</script>
 END
 ;
 
@@ -162,7 +200,7 @@ foreach (@nics) {
 	}
 }
 
-&Header::openpage($Lang::tr{"zoneconf title"}, 1, $css);
+&Header::openpage($Lang::tr{"zoneconf title"}, 1, $extraHead);
 &Header::openbigbox('100%', 'center');
 
 ### Evaluate POST parameters ###
@@ -312,8 +350,8 @@ if ($cgiparams{"ACTION"} eq $Lang::tr{"save"}) {
 print <<END
 <form method='post' enctype='multipart/form-data'>
 	<table>
-		<tr>
-		<td class="h narrow topleft" /td>
+	<tr>
+		<td class="h narrow topleft"></td>
 END
 ;
 
@@ -332,7 +370,7 @@ foreach (@zones) {
 		my $red_restricted = ($uc eq "RED" && ! ($red_type eq "STATIC" || $red_type eq "DHCP"));
 
 		if ($red_restricted) {
-			print "<td class='h textcenter $_'>$uc ($red_type)</td>";
+			print "\t\t<td class='h textcenter $_'>$uc ($red_type)</td>\n";
 
 			next; # We're done here
 		}
@@ -350,7 +388,7 @@ foreach (@zones) {
 	}
 
 	print <<END
-		<td class='h textcenter $_'>$uc</br>
+		<td class='h textcenter $_'>$uc<br>
 			<select name="MODE $uc">
 				<option value="DEFAULT" $mode_selected{"DEFAULT"}>$Lang::tr{"zoneconf nicmode default"}</option>
 				<option value="BRIDGE" $mode_selected{"BRIDGE"}>$Lang::tr{"zoneconf nicmode bridge"}</option>
@@ -361,7 +399,7 @@ END
 ;
 }
 
-print "</tr>";
+print "\t</tr>\n";
 
 my $slightlygrey = "";
 
@@ -370,12 +408,13 @@ foreach (@nics) {
 	my $nic = $_->[1];
 	my $wlan = $_->[2];
 
-	print "<tr><td class='h narrow textcenter'>$nic<br>$mac</td>";
+	print "\t<tr>\n\t\t<td class='h narrow textcenter'>$nic<br>$mac</td>\n";
 
 	# Iterate through all zones and check if the current NIC is assigned to it
 	foreach (@zones) {
 		my $uc = uc $_;
 		my $dev_name = $ethsettings{"${uc}_DEV"};
+		my $highlight = "";
 
 		if ($dev_name eq "") { # Again, skip the zone if it is not activated
 			next;
@@ -391,9 +430,10 @@ foreach (@nics) {
 
 				if ($mac eq $ethsettings{"${uc}_MACADDR"}) {
 					$checked = "checked";
+					$highlight = $_;
 				}
 
-				print "<td class='textcenter $slightlygrey'><input type='radio' id='PPPACCESS $mac' name='PPPACCESS' value='$mac' $checked></td>";
+				print "\t\t<td class='textcenter $highlight $slightlygrey'><input type='radio' id='PPPACCESS $mac' name='PPPACCESS' value='$mac' data-zone='RED' data-mac='$mac' onchange='highlightAccess(this)' $checked></td>\n";
 				next; # We're done here
 			}
 		}
@@ -430,21 +470,26 @@ foreach (@nics) {
 
 		$access_selected{"NONE"} = ($access_selected{"NATIVE"} eq "") && ($access_selected{"VLAN"} eq "") ? "selected" : "";
 		my $vlan_disabled = ($wlan) ? "disabled" : "";
+		
+		# If the interface is assigned, hightlight table cell
+		if ($access_selected{"NONE"} eq "") {
+			$highlight = $_;
+		}
 
 		print <<END
-			<td class="textcenter $slightlygrey">
-				<select name="ACCESS $uc $mac" onchange="document.getElementById('TAG $uc $mac').disabled = (this.value === 'VLAN' ? false : true)">
-					<option value="NONE" $access_selected{"NONE"}>- $Lang::tr{"zoneconf access none"} -</option>
-					<option value="NATIVE" $access_selected{"NATIVE"}>$Lang::tr{"zoneconf access native"}</option>
-					<option value="VLAN" $access_selected{"VLAN"} $vlan_disabled>$Lang::tr{"zoneconf access vlan"}</option>
-				</select>
-				<input type="number" class="vlanid" id="TAG $uc $mac" name="TAG $uc $mac" min="1" max="4095" value="$zone_vlan_id" $field_disabled>
-			</td>
+		<td class="textcenter $highlight $slightlygrey">
+			<select name="ACCESS $uc $mac" data-zone="$uc" data-mac="$mac" onchange="highlightAccess(this)">
+				<option value="NONE" $access_selected{"NONE"}>- $Lang::tr{"zoneconf access none"} -</option>
+				<option value="NATIVE" $access_selected{"NATIVE"}>$Lang::tr{"zoneconf access native"}</option>
+				<option value="VLAN" $access_selected{"VLAN"} $vlan_disabled>$Lang::tr{"zoneconf access vlan"}</option>
+			</select>
+			<input type="number" class="vlanid" id="TAG $uc $mac" name="TAG $uc $mac" min="1" max="4095" value="$zone_vlan_id" $field_disabled>
+		</td>
 END
 ;
 	}
 
-	print "</tr>";
+	print "\t</tr>\n";
 
 	if ($slightlygrey) {
 		$slightlygrey = "";