FRM-30403: Calculated item cannot specify a mirror item, or be specified as a mirror item.
项不能与公式项进行同步，会报FRM-30403错误。
但是可以复制公式项。
Error Message:
FRM-30403: Calculated item cannot specify a mirror item, or be specified as a mirror item.
Error Cause:
A calculated item specifies a Mirror Item, or is specified as a Mirror Item by some other item in the block.
Action:
Remove the Mirror Item property. To make two calculated items effectively mirror each other, make one a formula item whose formula is simply ':' followed by the name of the other calculated item.