Trustees having violated or attempted to violate any express trust, or becoming incompetent or insolvent, or of whose solvency or that of their sureties there is reasonable doubt, or for other cause, in the discretion of the court having jurisdiction, may, on petition of any person interested, after hearing, be removed by such court and denied compensation in whole or in part; and any beneficiary, cotrustee, or successor may treat the violation as a breach of trust; and all vacancies in express trusteeships may be filled by such court.