diff --git a/form.php b/form.php
index 919d446..0de6f99 100644
--- a/form.php
+++ b/form.php
@@ -781,6 +781,8 @@ class formfield
   {
     // No $this->multiple, $this->rows $this->cols $this->placeholder,
     //    $this->maxlength
+    if (! is_array ($this->titles) || count ($this->titles) === 0)
+      $this->titles = array ("");
     $res = "";
     $res .= "<div class='form-group";
     if (isset ($this->errors))
@@ -788,12 +790,17 @@ class formfield
     $res .= "'>\n";
     if ($this->label !== "")
     {
-      $res .= "    <label class='col-sm-$this->titlewidth control-label' for='".
-              $this->formName."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES);
-      if (is_array ($this->titles) && count ($this->titles) > 1)
-        $res .= "_0";
-      $res .= "'";
+      $res .= "    <label class='col-sm-$this->titlewidth control-label'";
+      if (is_array ($this->titles) && count ($this->titles) == 1 &&
+          reset ($this->titles) === "")
+      {
+        // If more than one title is set, the main label is unusable, so
+        // do not link it to the checkbox
+        // If there is no label on the checkbox, this label must be set
+        $res .= " for='".  $this->formName."_";
+        $res .= htmlspecialchars ($this->name, ENT_QUOTES);
+        $res .= "'";
+      }
       if (isset ($this->hidden) && $this->hidden !== FALSE)
         $res .= " style='display:none'";
       $res .= ">";
@@ -805,8 +812,6 @@ class formfield
       $res .= "</label>\n";
     }
     $res .= "    <div class='col-sm-$this->fieldwidth'>\n";
-    if (! is_array ($this->titles) || count ($this->titles) === 0)
-      $this->titles = array ("");
     foreach ($this->titles as $key=>$val)
     {
       $res .= " <div class='checkbox'>\n";
@@ -818,9 +823,9 @@ class formfield
       $res .= "' value='unset'";
       $res .= "/>";
       $res .= "<label for='$this->formName"."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES)."_";
+      $res .= htmlspecialchars ($this->name, ENT_QUOTES);
       if (count ($this->titles) > 1)
-        $res .= "$key";
+        $res .= "_$key";
       $res .= "'>";
       $res .= "<input type='checkbox'";
       $res .= " name='$this->formName"."[";
@@ -1010,9 +1015,17 @@ class formfield
     $res .= "'>\n";
     if ($this->label !== "")
     {
-      $res .= "    <label class='col-sm-$this->titlewidth control-label' for='".
-              $this->formName."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES)."_0'";
+      $res .= "    <label class='col-sm-$this->titlewidth control-label'";
+      if (is_array ($this->titles) && count ($this->titles) == 1 &&
+          reset ($this->titles) === "")
+      {
+        // If more than one title is set, the main label is unusable, so
+        // do not link it to the radio
+        // If there is no label on the checkbox, this label must be set
+        $res .= " for='".  $this->formName."_";
+        $res .= htmlspecialchars ($this->name, ENT_QUOTES);
+        $res .= "'";
+      }
       if (isset ($this->hidden) && $this->hidden !== FALSE)
         $res .= " style='display:none'";
       $res .= ">";
@@ -1499,6 +1512,8 @@ class formfield
   {
     // No $this->multiple, $this->rows $this->cols $this->placeholder,
     //    $this->maxlength
+    if (! is_array ($this->titles) || count ($this->titles) === 0)
+      $this->titles = array ("");
     $res = "";
     $res .= "<div class='form-group";
     if (isset ($this->errors))
@@ -1511,11 +1526,16 @@ class formfield
       $res .= "    <label";
       if ($this->titlewidth > 0)
         $res .= " class='col-sm-$this->titlewidth col-form-label'";
-      $res .= " for='". $this->formName."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES);
-      if (is_array ($this->titles) && count ($this->titles) > 1)
-        $res .= "_0";
-      $res .= "'";
+      if (is_array ($this->titles) && count ($this->titles) == 1 &&
+          reset ($this->titles) === "")
+      {
+        // If more than one title is set, the main label is unusable, so
+        // do not link it to the checkbox
+        // If there is no label on the checkbox, this label must be set
+        $res .= " for='".  $this->formName."_";
+        $res .= htmlspecialchars ($this->name, ENT_QUOTES);
+        $res .= "'";
+      }
       if (isset ($this->hidden) && $this->hidden !== FALSE)
         $res .= " style='display:none'";
       $res .= ">";
@@ -1527,8 +1547,6 @@ class formfield
       $res .= "</label>\n";
     }
     $res .= "    <div class='col-sm-$this->fieldwidth'>\n";
-    if (! is_array ($this->titles) || count ($this->titles) === 0)
-      $this->titles = array ("");
     foreach ($this->titles as $key=>$val)
     {
       $res .= "      <div class='form-check'>\n";
@@ -1602,9 +1620,9 @@ class formfield
       }
       $res .= "/>\n";
       $res .= "        <label for='$this->formName"."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES)."_";
+      $res .= htmlspecialchars ($this->name, ENT_QUOTES);
       if (count ($this->titles) > 1)
-        $res .= "$key";
+        $res .= "_$key";
       $res .= "' class ='form-check-label'";
       $res .= ">";
       $res .= "$val</label>\n";
@@ -1755,8 +1773,16 @@ class formfield
       $res .= "    <label";
       if ($this->titlewidth > 0)
         $res .= " class='col-sm-$this->titlewidth col-form-label'";
-      $res .= " for='". $this->formName."_";
-      $res .= htmlspecialchars ($this->name, ENT_QUOTES)."_0'";
+      if (is_array ($this->titles) && count ($this->titles) == 1 &&
+          reset ($this->titles) === "")
+      {
+        // If more than one title is set, the main label is unusable, so
+        // do not link it to the radio
+        // If there is no label on the checkbox, this label must be set
+        $res .= " for='".  $this->formName."_";
+        $res .= htmlspecialchars ($this->name, ENT_QUOTES);
+        $res .= "'";
+      }
       if (isset ($this->hidden) && $this->hidden !== FALSE)
         $res .= " style='display:none'";
       $res .= ">";