diff --git a/js/app/views/UploadPanelUI.js b/js/app/views/UploadPanelUI.js
index 1dac257..d5ed007 100644
--- a/js/app/views/UploadPanelUI.js
+++ b/js/app/views/UploadPanelUI.js
@@ -291,17 +291,19 @@ Ext.define('amdaUI.UploadPanelUI', {
 		});
 		
 		this.manualSampling = Ext.create('Ext.form.FieldContainer', { 
-			defaultType: 'textfield',
+			defaultType: 'numberfield',
 			layout: 'anchor',
 			defaults: {
 				layout: '100%',
-				labelWidth : 150
+				labelWidth : 150,
+				minValue : 0.001,
+				hideTrigger: true
 			}, 
 			hidden : true,
 			items: [  
 			{ 
 				fieldLabel : 'min sampling',	
-				name : 'min_manual_sampling'   
+				name : 'min_manual_sampling'
 			},  
 			{ 
 				fieldLabel : 'max sampling',	
--
libgit2 0.21.2