Description: TeXmacs crashes on trying to insert footers using Document > Page form.


Additional info:

Throwing segmentation fault
-------------------------------------------------
Error message:
segmentation fault

System information:
TeXmacs version : 1.99.5
Built by : builduser
Building date : Nov 19 2016
Operating system : linux-gnu
Vendor : pc
Processor : x86_64
Crash date : Wed Dec 20 06:56:21 EST 2017

Editor status:
Root path : [ 0 ]
Current path : [ 0, 0, 15 ]
Shifted path : [ 0, 0, 15 ]
Physical selection : [ 0, 0, 15 ] -- [ 0, 0, 15 ]

Backtrace of C++ stack:
texmacs.bin() [0xdb3f9f]
texmacs.bin() [0x49217c]
/usr/lib/libc.so.6 : () + 0x348e0
texmacs.bin() [0xa65372]
texmacs.bin() [0xa78569]
texmacs.bin() [0xa3851f]
texmacs.bin() [0xa8d525]
/usr/lib/libQtCore.so.4 : QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 0x79d
/usr/lib/libQtCore.so.4 : QObject::event(QEvent*) + 0xa3
/usr/lib/libQtGui.so.4 : QApplicationPrivate::notify_helper(QObject*, QEvent*) + 0x94
/usr/lib/libQtGui.so.4 : QApplication::notify(QObject*, QEvent*) + 0x22d
texmacs.bin() [0xa8dbeb]
/usr/lib/libQtCore.so.4 : QCoreApplication::notifyInternal(QObject*, QEvent*) + 0x8e
/usr/lib/libQtCore.so.4 : () + 0x1bea4c
/usr/lib/libQtCore.so.4 : () + 0x1bbb22
/usr/lib/libglib-2.0.so.0 : g_main_context_dispatch() + 0x310
/usr/lib/libglib-2.0.so.0 : () + 0x6cf69
/usr/lib/libglib-2.0.so.0 : g_main_context_iteration() + 0x2e
/usr/lib/libQtCore.so.4 : QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 0x78
/usr/lib/libQtGui.so.4 : () + 0x28af88
/usr/lib/libQtCore.so.4 : QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 0x44
/usr/lib/libQtCore.so.4 : QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 0x1bf
/usr/lib/libQtCore.so.4 : QCoreApplication::exec() + 0xa0
texmacs.bin() [0xda78e1]
/usr/lib/libguile.so.17 : () + 0x62e2f
/usr/lib/libguile.so.17 : () + 0x3a44a
/usr/lib/libguile.so.17 : scm_c_catch() + 0x258
/usr/lib/libguile.so.17 : scm_i_with_continuation_barrier() + 0xb4
/usr/lib/libguile.so.17 : scm_c_with_continuation_barrier() + 0x40
/usr/lib/libguile.so.17 : scm_i_with_guile_and_parent() + 0x36
/usr/lib/libguile.so.17 : scm_boot_guile() + 0x35
texmacs.bin() [0x43fc64]
/usr/lib/libc.so.6 : __libc_start_main() + 0xea
texmacs.bin() [0x4452aa]

-------------------------------------------------


Steps to reproduce:

1. Start TeXmacs.
2. Type a line of test. (e.g. "Hello, World")
3. Go to the menu bar and click Document > Page.
4. In the Document page format form, navigate to the Headers tab
5. Close the dialog. You should see the above C++ backtrace.