[Bugs] #4903 Sugar NORM: view source has no scroll bar

[Sugar Labs Bugs]

#4903: view source has no scroll bar
---------------------+-------------------------------------
  Reporter:  quozl   |            Owner:
      Type:  defect  |           Status:  new
  Priority:  Normal  |        Milestone:  Unspecified
 Component:  Sugar   |          Version:  Git as of bugdate
  Severity:  Major   |       Resolution:
  Keywords:          |  Distribution/OS:  OLPC
Bug Status:  New     |
---------------------+-------------------------------------

Comment (by quozl):

 '' "Great Scott!" '' -- Dr. Emmett Brown,
 [http://www.imdb.com/title/tt0088763/quotes Back to the Future].

 When reproducing on Fedora 18, at the instant the View Source key is
 pressed while viewing the Calculate help in the Help activity, shell.log
 receives these lines:

 {{{
 (main.py:1997): Gtk-WARNING **: gtk_scrolled_window_add(): cannot add non
 scrollable widget use gtk_scrolled_window_add_with_viewport() instead
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_vscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_hscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_vscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_hscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_vscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_hscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_vscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 (main.py:1997): Gtk-CRITICAL **: gtk_scrollable_get_hscroll_policy:
 assertion `GTK_IS_SCROLLABLE (scrollable)' failed
 }}}

 Which means that the code is assuming an object is scrolled when it is
 not.  That gives a reason why there are no scroll bars.

 Reverting
 [https://github.com/sugarlabs/sugar/commit/4be3f9e7f929efafdf48046ab8ae0e2ed0e746c8
 4be3f9e] fixes the problem.  See
 [http://dev.laptop.org/~quozl/z/1Zt8xB.txt my revert diff] if you need to
 try it or patch a deployment build.

 (Also, on Fedora 20, reverting 4be3f9e fixes the X server abort and quit
 and restart of Sugar.  It turns out this is one of the causes of
 olpc:12872 (desktop instability).  Debugging and tracing of the X server
 shows the client had sent impossible parameters in drawing operations.  It
 seems 4be3f9e made GTK+ send impossible parameters.  I'm very happy with
 this accidental discovery!)

 Now, the 4be3f9e patch was a fix for #4273 by @ignacio and @godiard.

 @ignacio, it seems from tests by you and Sam that this problem relates to
 the version of GTK+, so is there a way to rewrite your patch for #4273
 that works on Fedora 18 GTK+?  Is the object hierarchy strictly correct
 according to GTK+ requirements?  I'm not sure I'm reading the hierarchy
 properly.  I welcome your thoughts.

--
Ticket URL: <https://bugs.sugarlabs.org/ticket/4903#comment:6>
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