diff --git a/src/calibre/gui2/tweak_book/preview.py b/src/calibre/gui2/tweak_book/preview.py
index 6d8a8d1aa7..061ef86379 100644
--- a/src/calibre/gui2/tweak_book/preview.py
+++ b/src/calibre/gui2/tweak_book/preview.py
@@ -342,6 +342,9 @@ class Inspector(QWidget):
             self.view_to_debug.page().setDevToolsPage(self.view.page())
             self.layout.addWidget(self.view)
 
+    def sizeHint(self):
+        return QSize(1280, 600)
+
 
 class WebView(RestartingWebEngineView):
 
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index f31a336d49..0b68b47dba 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -323,6 +323,9 @@ class Inspector(QWidget):
             self.view_to_debug.page().setDevToolsPage(self.view.page())
             self.layout.addWidget(self.view)
 
+    def sizeHint(self):
+        return QSize(600, 1200)
+
 
 class WebView(RestartingWebEngineView):