make button available considering checking

ui/nG6/pi1/project_view.tpl

@@ -205,8 +205,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 								<th align="left" colspan="7">
 									With selection :
 									<div  class="btn-group">
-										<button id="add_user" type="button" class="btn btn-small"><i class="icon-plus"></i> add user</button>
-										<button id="del_user" type="button" class="btn btn-small"><i class="icon-minus"></i> delete user</button>
+										<button id="add_user" type="button" class="btn nou-selection-btn btn-small"><i class="icon-plus"></i> add user</button>
+										<button id="del_user" type="button" class="btn multipleu-selection-btn btn-small"><i class="icon-minus"></i> delete user</button>
 									</div>
 								</th>
 							</tr>

ui/nG6/res/js/tx_nG6_pi1.js

@@ -176,6 +176,14 @@ $(function () {
 	$("#chk_all_analysis").change(function() {
 		updateAnalysisButtonStatus();
 	});
+
+	updateUsersButtonStatus();
+	$("[id^=chk_user_]").change(function() {
+		updateUsersButtonStatus();
+	});
+	$("#chk_all_user").change(function() {
+		updateUsersButtonStatus();
+	});
 	
 	// Init tables
 	var projectTable = initProjectTable(),
@@ -651,6 +659,17 @@ function updateAnalysisButtonStatus() {
 	$(".noa-selection-btn").each(function(){ $(this).removeAttr('disabled'); });
 }
 
+function updateUsersButtonStatus() {
+	$('.multipleu-selection-btn').each(function(){
+       	if ($(":checked[id^=chk_user_]").size() == 0) {
+            $(this).attr('disabled', 'disabled');
+        } else if ($(":checked[id^=chk_user_]").size() > 0) {
+        	$(this).removeAttr('disabled');
+        }
+    });
+	$(".nou-selection-btn").each(function(){ $(this).removeAttr('disabled'); });
+}
+
 /* Run table init */
 function initRunTable() {
 	var runTable = null ;