_contrast->Bind (wxEVT_SCROLL_THUMBTRACK, bind (&VideoWaveformDialog::contrast_changed, this));
_plot->MouseMoved.connect (bind (&VideoWaveformDialog::mouse_moved, this, _1, _2, _3, _4));
_contrast->Bind (wxEVT_SCROLL_THUMBTRACK, bind (&VideoWaveformDialog::contrast_changed, this));
_plot->MouseMoved.connect (bind (&VideoWaveformDialog::mouse_moved, this, _1, _2, _3, _4));