diff --git a/core/src/main/resources/hudson/model/Project/configure-entries.jelly b/core/src/main/resources/hudson/model/Project/configure-entries.jelly
index 10b3ea1539b80e900c7c6c09ff19218bc617231e..c937e11b451901f413c091ec9fef67a332c5d0d3 100644
--- a/core/src/main/resources/hudson/model/Project/configure-entries.jelly
+++ b/core/src/main/resources/hudson/model/Project/configure-entries.jelly
@@ -87,7 +87,8 @@
                      checked="${!empty(up)}">
       <f:entry title="Projects names"
                description="Multiple projects can be specified like 'abc, def'">
-        <input class="setting-input" name="upstreamProjects"
+        <input class="setting-input validated" name="upstreamProjects"
+          checkUrl="'${rootURL}/publisher/BuildTrigger/check?value='+this.value"
           type="text" value="${h.getProjectListString(up)}"/>
       </f:entry>
     </f:optionalBlock>