diff --git a/Documentation/SOGoInstallationGuide.asciidoc b/Documentation/SOGoInstallationGuide.asciidoc
index 73e562e4c..6148ee942 100644
--- a/Documentation/SOGoInstallationGuide.asciidoc
+++ b/Documentation/SOGoInstallationGuide.asciidoc
@@ -1035,6 +1035,10 @@ not work for entries in this source and thus, freebusy lookups.
 |If set as an address book, the human identification name of the LDAP
 repository
 
+|listRequiresDot (optional)
+|If set to `YES`, listing of this LDAP source is only possible when performing a search (respecting the SOGoSearchMinimumWordLength parameter) or when explicitely typing a single dot.
+Defaults to `YES` when unset.
+
 |ModulesConstraints (optional)
 |Limits the access of any module through a constraint based on an LDAP
 attribute; must be a dictionary with keys `Mail`, and/or `Calendar`,
diff --git a/NEWS b/NEWS
index c2dd98748..944af02ef 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,8 @@ Enhancements
  - [web] improved confirm dialogs for deletions
  - [web] allow resources to prevent invitations (#3410)
  - [web] warn when double-booking attendees and offer force save option
+ - [web] list search now displays a warning regarding the minlength constraint
+ - [web] loading an LDAP-based addressbook is now instantaneous when listRequiresDot is disabled (#438, #3464)
  - [eas] now support EAS MIME truncation
 
 Bug fixes
diff --git a/UI/Common/English.lproj/Localizable.strings b/UI/Common/English.lproj/Localizable.strings
index 54f38f4a2..68d15c050 100644
--- a/UI/Common/English.lproj/Localizable.strings
+++ b/UI/Common/English.lproj/Localizable.strings
@@ -104,3 +104,6 @@
 "Loading" = "Loading";
 "No such user." = "No such user.";
 "You cannot (un)subscribe to a folder that you own!" = "You cannot (un)subscribe to a folder that you own!";
+
+/* Error message display bellow search field when the search string has less than the required number of characters */
+"Enter at least %{minimumSearchLength} characters" = "Enter at least %{minimumSearchLength} characters";
\ No newline at end of file
diff --git a/UI/Common/UIxPageFrame.m b/UI/Common/UIxPageFrame.m
index 0b78dfb4f..b748022d1 100644
--- a/UI/Common/UIxPageFrame.m
+++ b/UI/Common/UIxPageFrame.m
@@ -615,11 +615,6 @@
 	   );
 }
 
-- (int) minimumSearchLength
-{
-  return [[[context activeUser] domainDefaults] searchMinimumWordLength];
-}
-
 @end /* UIxPageFrame */
 
 @interface UIxSidenavToolbarTemplate : UIxComponent
diff --git a/UI/Contacts/UIxContactFoldersView.m b/UI/Contacts/UIxContactFoldersView.m
index 8b24dc109..016097c9c 100644
--- a/UI/Contacts/UIxContactFoldersView.m
+++ b/UI/Contacts/UIxContactFoldersView.m
@@ -339,6 +339,8 @@ Class SOGoContactSourceFolderK, SOGoGCSFolderK;
                                   [NSNumber numberWithBool: [currentFolder isKindOfClass: SOGoGCSFolderK]], @"isEditable",
                                   [NSNumber numberWithBool: [currentFolder isKindOfClass: SOGoContactSourceFolderK]
                                             && ![currentFolder isPersonalSource]], @"isRemote",
+                                  [NSNumber numberWithBool: [currentFolder isKindOfClass: SOGoContactSourceFolderK]
+                                            && [currentFolder listRequiresDot]], @"listRequiresDot",
                                   acls, @"acls",
                                   urls, @"urls",
                                   nil];
diff --git a/UI/SOGoUI/UIxComponent.h b/UI/SOGoUI/UIxComponent.h
index f4e5531c2..1b7cebd11 100644
--- a/UI/SOGoUI/UIxComponent.h
+++ b/UI/SOGoUI/UIxComponent.h
@@ -86,6 +86,10 @@
 /* SoUser */
 - (NSString *) shortUserNameForDisplay;
 
+/* Common defaults and settings */
+- (int) minimumSearchLength;
+- (NSString *) minimumSearchLengthLabel;
+
 /* labels */
 - (NSString *) labelForKey:(NSString *)_key;
 - (NSString *) commonLabelForKey:(NSString *)_key;
diff --git a/UI/SOGoUI/UIxComponent.m b/UI/SOGoUI/UIxComponent.m
index 46b368a46..0ab260b8f 100644
--- a/UI/SOGoUI/UIxComponent.m
+++ b/UI/SOGoUI/UIxComponent.m
@@ -22,6 +22,7 @@
 
 #import <Foundation/NSKeyValueCoding.h>
 #import <Foundation/NSUserDefaults.h> /* for locale strings */
+#import <Foundation/NSValue.h>
 
 #import <NGObjWeb/SoObjects.h>
 #import <NGObjWeb/WOResponse.h>
@@ -509,6 +510,22 @@ static SoProduct      *commonProduct      = nil;
   return [[context activeUser] login];
 }
 
+/* Common defaults and settings */
+
+- (int) minimumSearchLength
+{
+  return [[[context activeUser] domainDefaults] searchMinimumWordLength];
+}
+
+- (NSString *) minimumSearchLengthLabel
+{
+  NSDictionary *defaults;
+
+  defaults = [NSDictionary dictionaryWithObject: [NSNumber numberWithInt: [self minimumSearchLength]]
+                                         forKey: @"minimumSearchLength"];
+  return [defaults keysWithFormat: [self commonLabelForKey: @"Enter at least %{minimumSearchLength} characters"]];
+}
+
 /* labels */
 
 - (NSString *) labelForKey: (NSString *) _str
diff --git a/UI/Templates/ContactsUI/UIxContactFoldersView.wox b/UI/Templates/ContactsUI/UIxContactFoldersView.wox
index faece92cb..08d3ae3fd 100644
--- a/UI/Templates/ContactsUI/UIxContactFoldersView.wox
+++ b/UI/Templates/ContactsUI/UIxContactFoldersView.wox
@@ -274,17 +274,21 @@
             </md-button>
           </div>
           <!-- search mode -->
-          <div class="md-toolbar-tools sg-toolbar-secondary"
+          <form name="searchForm" class="md-toolbar-tools sg-toolbar-secondary"
                layout="row"
                ng-show="addressbook.mode.search"
-               sg-search="addressbook.selectedFolder.$filter(searchText, { search: searchField })">
+               sg-search="addressbook.selectedFolder.$filter(searchText, { search: searchField })"
+               sg-allow-dot="addressbook.selectedFolder.listRequiresDot">
             <md-button class="md-icon-button"
                        sg-search-cancel="addressbook.cancelSearch()"
                        label:aria-label="Back">
               <md-icon>arrow_back</md-icon>
             </md-button>
             <md-input-container class="md-flex" md-no-float="md-no-float">
-              <input name="folderSearch" type="search" label:placeholder="Search"/>
+              <input name="folderSearch" type="search" var:minlength="minimumSearchLength" label:placeholder="Search"/>
+              <div ng-messages="searchForm.folderSearch.$error" ng-show="searchForm.folderSearch.$dirty">
+                <div ng-message="minlength"><var:string value="minimumSearchLengthLabel"/></div>
+              </div>
             </md-input-container>
             <md-input-container flex="25">
               <md-select>
@@ -293,7 +297,7 @@
                 <md-option value="organization"><var:string label:value="Organization"/></md-option>
               </md-select>
             </md-input-container>
-          </div>
+          </form>
         </md-toolbar>
 
         <!-- multiple selection mode -->
@@ -362,7 +366,7 @@
             </span>
           </md-subheader>
           <md-subheader ng-hide="addressbook.service.$query.value">
-            <span ng-switch="addressbook.selectedFolder.isRemote">
+            <span ng-switch="addressbook.selectedFolder.listRequiresDot">
               <span ng-switch-when="1">
                 <var:string label:value="Start a search to browse this address book"/>
               </span>
diff --git a/UI/Templates/MailerUI/UIxMailFolderTemplate.wox b/UI/Templates/MailerUI/UIxMailFolderTemplate.wox
index 6465668c2..dab826b9f 100644
--- a/UI/Templates/MailerUI/UIxMailFolderTemplate.wox
+++ b/UI/Templates/MailerUI/UIxMailFolderTemplate.wox
@@ -116,10 +116,12 @@
         </md-button>
       </div>
       <!-- search mode -->
-      <div class="md-toolbar-tools sg-toolbar-secondary"
-           layout="row"
-           ng-show="mailbox.mode.search"
-           sg-search="mailbox.selectedFolder.$filter(null, [{ searchBy: searchField, searchInput: searchText }])">
+      <form class="md-toolbar-tools sg-toolbar-secondary"
+            name="searchForm"
+            layout="row"
+            ng-show="mailbox.mode.search"
+            sg-search="mailbox.selectedFolder.$filter(null, [{ searchBy: searchField, searchInput: searchText }])"
+            sg-allow-dot="false">
         <md-button class="sg-icon-button"
                    sg-search-cancel="mailbox.cancelSearch()"
                    label:aria-label="Back">
@@ -137,7 +139,7 @@
             <md-option value="body"><var:string label:value="Entire Message"/></md-option>
           </md-select>
         </md-input-container>
-      </div>
+      </form>
     </md-toolbar>
 
     <!-- multiple-selection mode -->
diff --git a/UI/Templates/SchedulerUI/UIxCalMainView.wox b/UI/Templates/SchedulerUI/UIxCalMainView.wox
index 425197b53..9cbf31ab6 100644
--- a/UI/Templates/SchedulerUI/UIxCalMainView.wox
+++ b/UI/Templates/SchedulerUI/UIxCalMainView.wox
@@ -457,10 +457,12 @@
             </md-button>
           </div>
           <!-- search mode -->
-          <div class="md-toolbar-tools sg-toolbar-secondary"
-               layout="row"
-               ng-show="list.mode.search"
-               sg-search="list.component.$filter(list.componentType, { value: searchText, search: searchField })">
+          <form class="md-toolbar-tools sg-toolbar-secondary"
+                name="searchForm"
+                layout="row"
+                ng-show="list.mode.search"
+                sg-search="list.component.$filter(list.componentType, { value: searchText, search: searchField })"
+                sg-allow-dot="false">
             <md-button class="md-icon-button"
                        sg-search-cancel="list.cancelSearch()"
                        label:aria-label="Back">
@@ -475,7 +477,7 @@
                 <md-option value="entireContent"><var:string label:value="Entire content"/></md-option>
               </md-select>
             </md-input-container>
-          </div>
+          </form>
         </md-toolbar>
 
         <!-- multiple-selection mode -->
diff --git a/UI/Templates/UIxPageFrame.wox b/UI/Templates/UIxPageFrame.wox
index 6c0b9efb2..61249cf71 100644
--- a/UI/Templates/UIxPageFrame.wox
+++ b/UI/Templates/UIxPageFrame.wox
@@ -53,11 +53,11 @@
           <!-- MAIN CONTENT ROW -->
           <var:component-content />
           
-          <!-- JAVASCRIPT IMPORTS -->
           <script type="text/javascript">
             var ApplicationBaseURL = '<var:string value="modulePath" />';
             var ResourcesURL = '<var:string value="applicationPath" />.woa/WebServerResources';
             var minimumSearchLength = <var:string value="minimumSearchLength" />;
+            var minimumSearchLengthLabel = '<var:string value="minimumSearchLengthLabel" />';
             <var:if condition="isUIxDebugEnabled">
               var DebugEnabled = true;
             </var:if>
@@ -121,6 +121,7 @@
           <script type="text/javascript" rsrc:src="js/vendor/angular-animate.min.js"><!-- space --></script>
           <script type="text/javascript" rsrc:src="js/vendor/angular-sanitize.min.js"><!-- space --></script>
           <script type="text/javascript" rsrc:src="js/vendor/angular-aria.min.js"><!-- space --></script>
+          <script type="text/javascript" rsrc:src="js/vendor/angular-messages.min.js"><!-- space --></script>
           <script type="text/javascript" rsrc:src="js/vendor/angular-material.js"><!-- space --></script>
           <script type="text/javascript" rsrc:src="js/vendor/angular-ui-router.min.js"><!-- space --></script>
 
diff --git a/UI/WebServerResources/js/Common/sgSearch.directive.js b/UI/WebServerResources/js/Common/sgSearch.directive.js
index 17b431120..38cc205a6 100644
--- a/UI/WebServerResources/js/Common/sgSearch.directive.js
+++ b/UI/WebServerResources/js/Common/sgSearch.directive.js
@@ -60,6 +60,13 @@
       return function postLink(scope, iElement, iAttr, controller) {
         var compiledButtonEl = iElement.find('button');
 
+        // Retrive the form and input names to check the form's validity in the controller
+        controller.formName = iElement.attr('name');
+        controller.inputName = inputEl.attr('name');
+
+        // Associate the sg-allow-dot parameter (boolean) to the controller
+        controller.allowDot = $parse(iElement.attr('sg-allow-dot'))(scope);
+
         // Associate callback to controller
         controller.doSearch = $parse(iElement.attr('sg-search'));
 
@@ -99,7 +106,6 @@
     minLength = angular.isNumber($window.minimumSearchLength)? $window.minimumSearchLength : 2;
 
     // Controller variables
-    vm.previous = { searchText: '', searchField: '' };
     vm.searchText = null;
 
     // Model options
@@ -113,20 +119,22 @@
 
     // Method to call on data changes
     vm.onChange = function() {
-      if (typeof vm.searchText !== 'undefined' && vm.searchText !== null) {
-        if (vm.searchText != vm.previous.searchText || vm.searchField != vm.previous.searchField) {
-          if (vm.searchText.length > minLength || vm.searchText.length === 0 || vm.searchText == '.') {
-            // doSearch is the compiled expression of the sg-search attribute
-            vm.doSearch($scope, { searchText: vm.searchText, searchField: vm.searchField });
-          }
-          vm.previous = { searchText: vm.searchText, searchField: vm.searchField };
-        }
+      var form = $scope[vm.formName],
+          input = form[vm.inputName],
+          rawSearchText = input.$viewValue;
+
+      if (vm.allowDot && rawSearchText == '.' || form.$valid) {
+        if (rawSearchText == '.')
+          // Ignore the minlength constraint when using the dot operator
+          input.$setValidity('minlength', true);
+
+        // doSearch is the compiled expression of the sg-search attribute
+        vm.doSearch($scope, { searchText: rawSearchText, searchField: vm.searchField });
       }
     };
 
     // Reset input field when cancelling the search
     vm.cancelSearch = function() {
-      vm.previous = { searchText: '', searchField: '' };
       vm.searchText = null;
     };
   }