qtiplot crash at edit intervals in add function

[Lord Panta]

Binary package hint: qtiplot

qtiplot crash at edit function intervals...

gateway mx-6938m
1.0 Gb Ram
1.7 GHz dual core
intel video 945gm 128 mb
ubuntu 10.04 lucyd
kernel 2.6.32.22
gnome 2.30.0
qtiplot version 0.9.7.10

how to reproduce:

1) open qtiplot
2) new graph
3) add function
4) in "From x" write some matematical operation... ej (pi/4) click everywhere... and
5) qtiplot crash

note: terminal message:

pierre@Desconocido:~$ qtiplot
terminate called after throwing an instance of 'std::bad_cast'
  what(): std::bad_cast
Cancelado

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: qtiplot 0.9.7.10+r1453-1ubuntu2
ProcVersionSignature: Ubuntu 2.6.32-22.33-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-22-generic i686
Architecture: i386
Date: Sun May 16 22:29:52 2010
ProcEnviron:
 LANG=es_MX.utf8
 SHELL=/bin/bash
SourcePackage: qtiplot