face to white mark after folding the panel EXTJS - extjs

Question

I have button on the first item of carousel on the Main View.
Button is managed by ButtonController and opens Form.
This form have tools: close, hide. When I click on close or hide tool on the forms after, for example closing I see white artifact. This looks like mark of header of Form..
enter image description here
Maybe this can be decided by trivial action?
Thanks
UPD: some code.
part of controller:
Ext.define('Foresto.view.main.ButtonController', {
extend: 'Ext.app.ViewController',
alias: 'controller.comenuform',
layout: 'vbox',
requires: [
'Foresto.view.forms.1',
'Foresto.view.forms.2',
'Foresto.view.forms.3',
'Foresto.view.forms.4'
],
views: ['Foresto.view.main.Main'],
cutForms: function () {
Ext.create('Ext.panel.Panel', {
layout: 'fit',
renderTo: 'mainPart',
autoshow: true,
items: [{
xtype: 'formsType4'
}]
})
},
part of form:
Ext.define('Foresto.view.forms.Formf', {
extend: 'Ext.form.Panel',
title: 'testApp',
header: {
cls: 'header-cls',
},
tools: [
{type: 'minimize',
handler: function(){
this.up("panel").hide();
}},
{type: 'save'},
{type:'close',
handler: function(){
this.up("panel").close();
}},
],
xtype: 'formsType4',
url: 'save-form.php',
defaults: {
xtype: 'selectfield',
labelWrap: true,
afterLabelTextTpl: [
'<span style="color:red;font-weight:normal" data-qtip="Required">*</span>'
]
},
items: [{...
and code of main:
Ext.define('Foresto.view.main.Main', {
extend: 'Ext.form.Panel',
id:'control-panel',
xtype: 'app-main',
controller:'comenuform',
requires: [
'Foresto.view.map.Map',
'Foresto.view.main.ButtonController',
],
padding: 0,
id:"bighBox",
header: {
cls: 'header-cls',
title : {
cls : 'header-title-cls',
text : 'MyApp'
}
},
tools: [{
type: 'menu',
handler: function(me) {
var cp = me.down('panel');
if (cp._hidden)
cp.show(true);
else
cp.hide(true);
}
}],
items:[{
xtype: 'carousel',
id: "mainPart",
flex: 1,
defaults: {
border: true,
ui: 'light'
},
items: [{
layout: {
type: 'vbox',
align: 'middle',
pack: 'center'
},
cls: 'colorful2',
defaults: {
border: true,
ui: 'light',
flex: 1
},
items:[{
xtype:'button',
cls: 'button-cls',
text: 'buttonOfForm4',
id: "RenterId",
margin: 10,
width: 920,
height: 250,
length: 150,
handler: 'renterForms'
... (some other buttons, which call forms too)..