diff --git a/module/group/view/privbygroup.html.php b/module/group/view/privbygroup.html.php
index 66c6b83b16..f1b357891f 100644
--- a/module/group/view/privbygroup.html.php
+++ b/module/group/view/privbygroup.html.php
@@ -38,7 +38,7 @@
         <th class='text-right'></th>
         <td class='form-actions'>
           <?php echo html::submitButton('', "onclick='setNoChecked()'");?>
-          <?php echo html::backButton();?>
+          <?php echo html::a($this->inlink('browse'), $lang->goback, '', "class='btn btn-back btn-wide'");?>
           <?php echo html::hidden('noChecked'); // Save the value of no checked.?>
         </td>
       </tr>
@@ -130,7 +130,7 @@
         </th>
         <td class='form-actions' colspan='2'>
           <?php echo html::submitButton('', "onclick='setNoChecked()'", 'btn btn-wide btn-primary');?>
-          <?php echo html::backButton();?>
+          <?php echo html::a($this->inlink('browse'), $lang->goback, '', "class='btn btn-back btn-wide'");?>
           <?php echo html::hidden('noChecked'); // Save the value of no checked.?>
         </td>
       </tr>
diff --git a/module/task/model.php b/module/task/model.php
index f58792395c..890597f921 100644
--- a/module/task/model.php
+++ b/module/task/model.php
@@ -1216,7 +1216,7 @@ class taskModel extends model
         {
             if($task->status == 'done' and $task->consumed == false) die(js::error('task#' . $taskID . sprintf($this->lang->error->notempty, $this->lang->task->consumedThisTime)));
             if($task->status == 'cancel') continue;
-            if($task->estStarted > $task->deadline) die(js::error('task#' . $taskID . $this->lang->task->error->deadlineSmall));
+            if(!empty($task->deadline) and $task->estStarted > $task->deadline) die(js::error('task#' . $taskID . $this->lang->task->error->deadlineSmall));
             foreach(explode(',', $this->config->task->edit->requiredFields) as $field)
             {
                 $field = trim($field);
diff --git a/module/task/view/batchedit.html.php b/module/task/view/batchedit.html.php
index 637ff9a981..f67a02544b 100755
--- a/module/task/view/batchedit.html.php
+++ b/module/task/view/batchedit.html.php
@@ -128,12 +128,12 @@ js::set('dittoNotice', $dittoNotice);
             <td class='text-left<?php echo zget($visibleFields, 'assignedTo', ' hidden')?>' style='overflow:visible'><?php echo html::select("assignedTos[$taskID]", $taskMembers, $tasks[$taskID]->assignedTo, "class='form-control chosen' {$disableAssignedTo}");?></td>
             <td><?php echo html::select("types[$taskID]",    $typeList, $tasks[$taskID]->type, "class='form-control'");?></td>
             <td <?php echo zget($visibleFields, 'status',     "class='hidden'")?>><?php echo html::select("statuses[$taskID]", $statusList, $tasks[$taskID]->status, "class='form-control'");?></td>
-            <td <?php echo zget($visibleFields, 'estStarted', "class='hidden'")?>><?php echo html::input("estStarteds[$taskID]",     $tasks[$taskID]->estStarted, "class='form-control text-center form-date'");?></td>
-            <td <?php echo zget($visibleFields, 'deadline',   "class='hidden'")?>><?php echo html::input("deadlines[$taskID]",     $tasks[$taskID]->deadline, "class='form-control text-center form-date'");?></td>
-            <td <?php echo zget($visibleFields, 'pri',        "class='hidden'")?>><?php echo html::select("pris[$taskID]",     $priList, $tasks[$taskID]->pri, "class='form-control'");?></td>
+            <td <?php echo zget($visibleFields, 'estStarted', "class='hidden'")?>><?php echo html::input("estStarteds[$taskID]", helper::isZeroDate($tasks[$taskID]->estStarted) ? '' : $tasks[$taskID]->estStarted, "class='form-control text-center form-date'");?></td>
+            <td <?php echo zget($visibleFields, 'deadline',   "class='hidden'")?>><?php echo html::input("deadlines[$taskID]", helper::isZeroDate($tasks[$taskID]->deadline) ? '' : $tasks[$taskID]->deadline, "class='form-control text-center form-date'");?></td>
+            <td <?php echo zget($visibleFields, 'pri',        "class='hidden'")?>><?php echo html::select("pris[$taskID]", $priList, $tasks[$taskID]->pri, "class='form-control'");?></td>
             <td <?php echo zget($visibleFields, 'estimate',   "class='hidden'")?>><?php echo html::input("estimates[$taskID]", $tasks[$taskID]->estimate, "class='form-control text-center' {$disableHour}");?></td>
             <td <?php echo zget($visibleFields, 'record',     "class='hidden'")?>><?php echo html::input("consumeds[$taskID]", '', "class='form-control text-center' {$disableHour}");?></td>
-            <td <?php echo zget($visibleFields, 'left',       "class='hidden'")?>><?php echo html::input("lefts[$taskID]",     $tasks[$taskID]->left, "class='form-control text-center' {$disableHour}");?></td>
+            <td <?php echo zget($visibleFields, 'left',       "class='hidden'")?>><?php echo html::input("lefts[$taskID]", $tasks[$taskID]->left, "class='form-control text-center' {$disableHour}");?></td>
             <td class='text-left<?php echo zget($visibleFields, 'finishedBy', ' hidden')?>' style='overflow:visible'><?php echo html::select("finishedBys[$taskID]", $members, $tasks[$taskID]->finishedBy, "class='form-control chosen'");?></td>
             <td class='text-left<?php echo zget($visibleFields, 'canceledBy', ' hidden')?>' style='overflow:visible'><?php echo html::select("canceledBys[$taskID]", $members, $tasks[$taskID]->canceledBy, "class='form-control chosen'");?></td>
             <td class='text-left<?php echo zget($visibleFields, 'closedBy', ' hidden')?>' style='overflow:visible'><?php echo html::select("closedBys[$taskID]",   $members, $tasks[$taskID]->closedBy, "class='form-control chosen'");?></td>
diff --git a/module/task/view/edit.html.php b/module/task/view/edit.html.php
index e1931015f9..57ca6fd300 100644
--- a/module/task/view/edit.html.php
+++ b/module/task/view/edit.html.php
@@ -175,11 +175,11 @@
             <table class='table table-form'>
               <tr>
                 <th class='thWidth'><?php echo $lang->task->estStarted;?></th>
-                <td><?php echo html::input('estStarted', $task->estStarted, "class='form-control form-date'");?></td>
+                <td><?php echo html::input('estStarted', helper::isZeroDate($task->estStarted) ? '' : $task->estStarted, "class='form-control form-date'");?></td>
               </tr>
               <tr>
                 <th><?php echo $lang->task->deadline;?></th>
-                <td><?php echo html::input('deadline', $task->deadline, "class='form-control form-date'");?></td>
+                <td><?php echo html::input('deadline', helper::isZeroDate($task->deadline) ? '' : $task->deadline, "class='form-control form-date'");?></td>
               </tr>
               <tr>
                 <th><?php echo $lang->task->estimate;?></th>