diff --git a/templates/repo/issue/view_content/sidebar.tmpl b/templates/repo/issue/view_content/sidebar.tmpl
index f403fa7cc7..f0e4f96cfa 100644
--- a/templates/repo/issue/view_content/sidebar.tmpl
+++ b/templates/repo/issue/view_content/sidebar.tmpl
@@ -211,7 +211,7 @@
 
 		<div class="ui divider"></div>
 		<span class="text"><strong>{{.i18n.Tr "repo.issues.due_date"}}</strong></span>
-		{{if gt .Issue.DeadlineUnix 0}}
+		{{if ne .Issue.DeadlineUnix 0}}
 			<p>
 				<span class="octicon octicon-calendar"></span>
 				{{.Issue.DeadlineUnix.FormatShort}}
@@ -229,12 +229,12 @@
 		{{end}}
 
 		{{if and .IsSigned .IsRepositoryWriter}}
-			<form method="POST"{{if gt .Issue.DeadlineUnix 0}}style="display: none;"{{end}}} id="add_deadline_form" action="{{$.RepoLink}}/issues/{{.Issue.Index}}/deadline/update" class="ui action input fluid">
+			<form method="POST" {{if ne .Issue.DeadlineUnix 0}}style="display: none;"{{end}} id="add_deadline_form" action="{{$.RepoLink}}/issues/{{.Issue.Index}}/deadline/update" class="ui action input fluid">
 				{{$.CsrfTokenHtml}}
 				<div class="ui fluid action input">
-					<input required placeholder="{{.i18n.Tr "repo.issues.due_date_form"}}" {{if gt .Issue.DeadlineUnix 0}}value="{{.Issue.DeadlineUnix.Format "2006-01-02"}}"{{end}} type="date" name="date" style="min-width: 13.9rem;border-radius: 4px 0 0 4px;border-right: 0;white-space: nowrap;">
+					<input required placeholder="{{.i18n.Tr "repo.issues.due_date_form"}}" {{if ne .Issue.DeadlineUnix 0 }}value="{{.Issue.DeadlineUnix.Format "2006-01-02"}}"{{end}} type="date" name="date" style="min-width: 13.9rem;border-radius: 4px 0 0 4px;border-right: 0;white-space: nowrap;">
 					<button class="ui green icon button">
-					{{if gt .Issue.DeadlineUnix 0}}
+					{{if ne .Issue.DeadlineUnix 0}}
 							<i class="edit icon"></i>
 					{{else}}
 							<i class="plus icon"></i>