re-add Hide to menu because not all WMs will add a minimize button to the title bar; add WM hint so that tiling WMs might float it instead

src/gui/src/MainWindow.cpp

@@ -96,6 +96,13 @@ MainWindow::MainWindow(QSettings& settings, AppConfig& appConfig) :
     m_pSslCertificate(NULL),
     m_pLogWindow(new LogWindow(nullptr))
 {
+    // explicitly unset DeleteOnClose so the window can be show and hidden
+    // repeatedly until Barrier is finished
+    setAttribute(Qt::WA_DeleteOnClose, false);
+    // mark the windows as sort of "dialog" window so that tiling window
+    // managers will float it by default (X11)
+    setAttribute(Qt::WA_X11NetWmWindowTypeDialog, true);
+
     setupUi(this);
 
     createMenuBar();
@@ -230,6 +237,7 @@ void MainWindow::createMenuBar()
 
     m_pMenuBarrier->addAction(m_pActionShowLog);
     m_pMenuBarrier->addAction(m_pActionSettings);
+    m_pMenuBarrier->addAction(m_pActionMinimize);
     m_pMenuBarrier->addSeparator();
     m_pMenuBarrier->addAction(m_pActionSave);
     m_pMenuBarrier->addSeparator();

src/gui/src/MainWindowBase.ui

@@ -350,7 +350,7 @@
     <string>Hide</string>
    </property>
    <property name="shortcut">
-    <string notr="true"/>
+    <string notr="true">F5</string>
    </property>
   </action>
   <action name="m_pActionRestore">