diff --git a/htdocs/product/list.php b/htdocs/product/list.php
index e1eed666587..9d4dbb3f716 100644
--- a/htdocs/product/list.php
+++ b/htdocs/product/list.php
@@ -126,7 +126,14 @@ $type = GETPOST("type", 'alpha');
 // Show/hide child product variants
 $show_childproducts = 0;
 if (isModEnabled('variants')) {
-	$show_childproducts = GETPOST('search_show_childproducts');
+	// An HTML checkbox does not submit anything when unchecked, so a hidden
+	// "search_show_childproducts=0" companion field is emitted next to the
+	// checkbox (see below). GETPOSTISSET() then lets us distinguish a
+	// resubmission with the checkbox off from a request that does not carry
+	// the filter at all, and the value is read as a strict 0/1 flag.
+	if (GETPOSTISSET('search_show_childproducts')) {
+		$show_childproducts = GETPOSTINT('search_show_childproducts');
+	}
 }
 
 $diroutputmassaction = $conf->product->dir_output.'/temp/massgeneration/'.$user->id;
@@ -383,7 +390,7 @@ if (empty($reshook)) {
 		$search_finished = '';
 		//$search_type='';						// There is 2 types of list: a list of product and a list of services. No list with both. So when we clear search criteria, we must keep the filter on type.
 
-		$show_childproducts = '';
+		$show_childproducts = 0;
 		$search_import_key = '';
 		$search_accountancy_code_sell = '';
 		$search_accountancy_code_sell_intra = '';
@@ -829,7 +836,7 @@ if ($fourn_id > 0) {
 	$param .= "&fourn_id=".urlencode((string) ($fourn_id));
 }
 if ($show_childproducts) {
-	$param .= ($show_childproducts ? "&search_show_childproducts=".urlencode($show_childproducts) : "");
+	$param .= "&search_show_childproducts=".urlencode((string) $show_childproducts);
 }
 if ($type != '') {
 	$param .= '&type='.urlencode((string) ($type));
@@ -979,7 +986,11 @@ if (isModEnabled('category') && $user->hasRight('categorie', 'read')) {
 // Show/hide child variant products
 if (isModEnabled('variants')) {
 	$moreforfilter .= '<div class="divsearchfield">';
-	$moreforfilter .= '<input type="checkbox" id="search_show_childproducts" name="search_show_childproducts"'.($show_childproducts ? 'checked="checked"' : '').'>';
+	// Companion hidden field ensures search_show_childproducts is always
+	// posted, even when the checkbox below is unchecked, so the unchecked
+	// state survives the filter/pagination submit and is parsed as 0/1.
+	$moreforfilter .= '<input type="hidden" name="search_show_childproducts" value="0">';
+	$moreforfilter .= '<input type="checkbox" id="search_show_childproducts" name="search_show_childproducts" value="1"'.($show_childproducts ? ' checked="checked"' : '').'>';
 	$moreforfilter .= ' <label for="search_show_childproducts">'.$langs->trans('ShowChildProducts').'</label>';
 	$moreforfilter .= '</div>';
 }