Restore inspector functionality for the preview pane

src/calibre/gui2/tweak_book/preview.py

@@ -4,10 +4,8 @@
 from __future__ import absolute_import, division, print_function, unicode_literals
 
 # TODO:
-# inspect element
 # live css
 # check that clicking on both internal and external links works
-# check if you can remove the restriction that prevents inspector dock from being undocked
 # check syncing of position back and forth
 # check all buttons in preview panel
 # pass user stylesheet with css for split
@@ -362,6 +360,7 @@ class WebView(QWebEngineView):
         w = QApplication.instance().desktop().availableGeometry(self).width()
         self._size_hint = QSize(int(w/3), int(w/2))
         self._page = WebPage(self)
+        self._page.setDevToolsPage(self.inspector.page())
         self.setPage(self._page)
         self.clear()
         self.setAcceptDrops(False)
@@ -392,10 +391,9 @@ class WebView(QWebEngineView):
             '''))
 
     def inspect(self):
-        raise NotImplementedError('TODO: Implement this')
-        # self.inspector.parent().show()
-        # self.inspector.parent().raise_()
-        # self.pageAction(self.page().InspectElement).trigger()
+        self.inspector.parent().show()
+        self.inspector.parent().raise_()
+        self.pageAction(QWebEnginePage.InspectElement).trigger()
 
     def contextMenuEvent(self, ev):
         menu = QMenu(self)

src/calibre/gui2/tweak_book/ui.py

@@ -730,7 +730,6 @@ class Main(MainWindow):
         self.preview.inspector.setParent(d)
         self.addDockWidget(Qt.BottomDockWidgetArea, d)
         d.close()  # By default the inspector window is closed
-        d.setFeatures(d.DockWidgetClosable | d.DockWidgetMovable)  # QWebInspector does not work in a floating dock
 
         d = create(_('Table of Contents'), 'toc-viewer')
         d.setAllowedAreas(Qt.LeftDockWidgetArea | Qt.RightDockWidgetArea | Qt.BottomDockWidgetArea | Qt.TopDockWidgetArea)