void TableModelVariablesAssigned::sourceVariablesChanged()
{
	emit assignmentsChanging();

	const Terms &variables = _source->allVariables();
	Terms variablesToKeep;
	bool variableRemoved = false;

	variablesToKeep.set(_variables);
	variableRemoved = variablesToKeep.discardWhatDoesntContainTheseComponents(variables);

	if (variableRemoved)
		setAssigned(variablesToKeep);

	emit assignmentsChanged();
}