Okay, this is workaround over ping timeouts problem on the server. Could make server crash if recieve thread wakes up after second ping timeout event.
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>600</width>
<height>400</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<layout class="QGridLayout" name="gridLayout" rowstretch="3,1">
<item row="1" column="2">
<widget class="QPlainTextEdit" name="plainTextEdit"/>
</item>
<item row="0" column="0" rowspan="2">
<layout class="QVBoxLayout" name="verticalLayout">
<item>
<widget class="QPushButton" name="pbUndo">
<property name="text">
<string>Undo</string>
</property>
</widget>
</item>
<item>
<spacer name="verticalSpacer">
<property name="orientation">
<enum>Qt::Vertical</enum>
</property>
<property name="sizeHint" stdset="0">
<size>
<width>20</width>
<height>40</height>
</size>
</property>
</spacer>
</item>
<item>
<widget class="QPushButton" name="pbSave">
<property name="text">
<string>Save</string>
</property>
</widget>
</item>
<item>
<widget class="QPushButton" name="pbLoad">
<property name="text">
<string>Load</string>
</property>
</widget>
</item>
<item>
<widget class="QSpinBox" name="sbBytes">
<property name="readOnly">
<bool>true</bool>
</property>
<property name="buttonSymbols">
<enum>QAbstractSpinBox::NoButtons</enum>
</property>
<property name="suffix">
<string> bytes</string>
</property>
<property name="maximum">
<number>999999</number>
</property>
</widget>
</item>
</layout>
</item>
<item row="0" column="2">
<widget class="DrawMapWidget" name="drawMapWidget" native="true"/>
</item>
</layout>
</widget>
</widget>
<layoutdefault spacing="6" margin="11"/>
<customwidgets>
<customwidget>
<class>DrawMapWidget</class>
<extends>QWidget</extends>
<header>drawmapwidget.h</header>
<container>1</container>
</customwidget>
</customwidgets>
<resources/>
<connections/>
</ui>