Make hitTestResult work with frames correctly

TODO

@@ -77,8 +77,6 @@ Bugs
 
 - Hinting problems on http://wiki.gentoo.org/wiki/Lenovo_ThinkPad_T440s (top navbar, e.g. lists, etc.)
 
-- clicking on text fields at https://bugreports.qt-project.org/secure/Dashboard.jspa doesn't go into insert mode. (because of iframes?)
-
 - scroll_page doesn't care about always visible bars, so content gets hidden
   e.g. http://www.mtb-news.de/forum/t/welcher-schuh-five-ten-vs-oneal.529148/
 

qutebrowser/widgets/webview.py

@@ -358,7 +358,10 @@ class WebView(QWebView):
             # sometimes.
             logging.debug("Clicked at {} but frame is None!".format(pos))
             return super().mousePressEvent(e)
-        pos -= frame.geometry().topLeft()
+        # You'd think we have to subtract frame.geometry().topLeft() from the
+        # position, but it seems QWebFrame::hitTestContent wants a position
+        # relative to the QWebView, not to the frame. This makes no sense to
+        # me, but it works this way.
         hitresult = frame.hitTestContent(pos)
         if self._is_editable(hitresult):
             logging.debug("Clicked editable element!")