diff --git a/koha-tmpl/intranet-tmpl/default/es/acqui.simple/addbiblio.tmpl b/koha-tmpl/intranet-tmpl/default/es/acqui.simple/addbiblio.tmpl
index eb64b311c7..f7c455a271 100644
--- a/koha-tmpl/intranet-tmpl/default/es/acqui.simple/addbiblio.tmpl
+++ b/koha-tmpl/intranet-tmpl/default/es/acqui.simple/addbiblio.tmpl
@@ -49,6 +49,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</tmpl_loop>
@@ -70,6 +71,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -91,6 +93,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
        </tr>
 	</TMPL_LOOP>
@@ -112,6 +115,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 		</tr>
 	</TMPL_LOOP>
@@ -133,6 +137,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -154,6 +159,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -175,6 +181,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -196,6 +203,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -217,6 +225,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -238,6 +247,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -257,6 +267,7 @@
 			<input type="hidden" name="tag" value="<TMPL_VAR name="tag">">
 			<input type="hidden" name="subfield" value="<TMPL_VAR name="subfield">">
 			<input type="hidden" name="mandatory" value="<TMPL_VAR name="mandatory">">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 		</td>
 	</tr>
 	</TMPL_LOOP>
@@ -271,6 +282,7 @@
 		<input type="hidden" name="subfield" value="<TMPL_VAR name="oldbiblioitemnumtagsubfield">">
 		<input type="hidden" name="field_value" value="<TMPL_VAR name="oldbiblioitemnumber">">
 		<input type="hidden" name="mandatory" value="0">
+			<input type="hidden" name="tag_mandatory" value="<TMPL_VAR name="tag_mandatory">">
 	</TMPL_IF>
 </form>
 
@@ -293,25 +305,58 @@ function active(numlayer)
 	}
 }
 function Check(f) {
-	var total_errors=0;
-//	alert(f.field_value.length);
+	// Scan for nonempty fields
+	var field_is_nonempty_p = new Array();
+	for (i=0 ; i<f.field_value.length ; i++) {
+	    field_is_nonempty_p[f.tag[i].value] = 0;
+	}
+	for (i=0 ; i<f.field_value.length ; i++) {
+	    if (f.field_value[i].value.length != 0) {
+		field_is_nonempty_p[f.tag[i].value] += 1;
+	    }
+	}
+
+	// Scan for missing mandatory subfields
+	var total_missing_mandatory_subfields = 0;
 	for (i=0 ; i<f.field_value.length-2 ; i++) {
-//	alert (f.field_value[i].value);
 		if (f.field_value[i].value.length==0 && f.mandatory[i].value==1) {
+		    // We should not flag an error unless the tag is also
+		    // mandatory, or if something else in the tag is entered
+
+		    if (f.tag_mandatory[i].value == 1 || field_is_nonempty_p[f.tag[i].value]) {
 			document.getElementById("error"+i).style.backgroundColor="#FF0000";
-			total_errors++;
+			total_missing_mandatory_subfields++;
+		    }
 		} else {
 			document.getElementById("error"+i).style.backgroundColor="#FFFFFF";
 		}
 	}
+
+	// Scan for missing mandatory tags
+	var total_missing_mandatory_tags = 0;
+	var seen_mandatory_tag_p = new Array();
+	for (i=0 ; i<f.field_value.length ; i++) {
+	    var j = f.tag[i].value;
+	    if (!field_is_nonempty_p[j] && f.tag_mandatory[i].value == 1) {
+		if (seen_mandatory_tag_p[j] != 1) {
+		    seen_mandatory_tag_p[j] = 1;
+		    total_missing_mandatory_tags++;
+		}
+		document.getElementById("error"+i).style.backgroundColor="#ffff00";
+	    }
+	}
+
+	var total_errors = total_missing_mandatory_tags + total_missing_mandatory_subfields;
 	var alertString2;
-	if (total_errors==0) {
-		document.f.submit();
-	} else {
+	if (total_errors!=0) {
 		alertString2 = "No se envío el formulario por los siguientes problemas\n";
 		alertString2 += "------------------------------------------------------------------------------------\n\n";
+//		alertString2 += "- "+ total_missing_mandatory_tags +" mandatory tags empty\n";
+//		alertString2 += "- "+ total_missing_mandatory_subfields +" mandatory fields empty (see bold subfields)";
 		alertString2 += "- "+ total_errors+" campos vacíos (revise los campos en negrita)";
 		alert(alertString2);
+	} else {
+		document.f.submit();
 	}
 }
 function Dopop(link,i) {