layout->add_constraint(*group, (i==0 ? GLtk::Layout::BELOW : GLtk::Layout::RIGHT_OF), *prev);
if(i>0)
layout->add_constraint(*group, GLtk::Layout::ALIGN_TOP, *prev);
GLtk::Layout &group_layout = group->get_or_create_layout();
layout->add_constraint(*group, (i==0 ? GLtk::Layout::BELOW : GLtk::Layout::RIGHT_OF), *prev);
if(i>0)
layout->add_constraint(*group, GLtk::Layout::ALIGN_TOP, *prev);
GLtk::Layout &group_layout = group->get_or_create_layout();