div for gallery was not correctly hidden

The div for the gallery was not hidden, because VueJS did evaluate
an empty list as false.

pdb-ui/src/main/resources/resources/js/ui.js

@@ -224,7 +224,7 @@ Vue.component('result-view-gallery', {
 	},
 	template: `
 	<div id="result-view-gallery"
-		v-if="gallery.tiles">
+		v-show="gallery.tiles">
 		<div 
 			class="card-grid-300"
 			v-show="!gallery.image">
@@ -958,7 +958,7 @@ function hidePlotAndGallery()
 {
 	data.resultView.imageUrl = '';
 	data.resultView.errorMessage = '';
-	data.gallery.tiles = [];
+	data.gallery.tiles = false;
 	data.gallery.image = "";
 }
 
@@ -1096,6 +1096,7 @@ function createGallery(vm){
 		// reset progress bar
 		data.gallery.progress.max = fieldValues.length;
 		data.gallery.progress.value = 0;
+		data.gallery.tiles = [];
 		
 		createGalleryItem(originalQuery, splitByField, imageHeight, imageWidth);
 	});