Allow Transform effect applied to an object to transform its the opacity mask also
If I apply Transform effect to an object with an opacity mask (to move or scale it parametrically, for example), only the object will be transformed — but not the contents of its opacity mask.
This is not consistent with the destructive method, when you actually move or scale this object...
The workaround is to apply the same effect to the contents of the opacity mask, but it does not always have the same effect, since the contents can have different bounds, and the transformation points will differ.
There should be an 'Affect Opacity Mask' option in the Transform effect dialog.