MyFrameMain: fix status bar handling for fullscreen and restore

Before, the status bar was hidden, but a dedicated area could still be seen.

re #222

src/gui/MyFrameMain.cpp

@@ -651,8 +651,9 @@ void MyFrameMain::onFullScreenChanged(wxFullScreenEvent &event) {
 	splitwinlayout();
         // hide toolbar labels
         GetToolBar()->SetWindowStyle(GetToolBar()->GetWindowStyle() & ~wxTB_TEXT);
-        // hide status bar
+        // hide and unlink status bar
         GetStatusBar()->Hide();
+        SetStatusBar(nullptr);
     } else {
 	// untick menu item
 	frame_main_menubar->Check(ID_FULLSCREEN, false);
@@ -671,9 +672,12 @@ void MyFrameMain::onFullScreenChanged(wxFullScreenEvent &event) {
 	splitwinlayout();
         // show toolbar labels
         GetToolBar()->SetWindowStyle(GetToolBar()->GetWindowStyle() | wxTB_TEXT);
-        // show status bar
+        // reattach and status bar
+        SetStatusBar(frame_main_statusbar);
         GetStatusBar()->Show();
   }
+    // needed at least on MacOS to let the status bar re-appear correctly on restore
+    SendSizeEvent();
 }