property Layer.Idem as Variant
Ensures that the layer's offset and rotation-angle is equal for all idem layers (separated by comma character).

TypeDescription
Variant A long expression that specifies the index of the layer idem with current layer, a string expression that specifies the key of the layer idem with the current layer, or a list of keys separated by comma character. For instance, Idem = "0,1" indicates that the current layer's rotation-angle and offset are always the same as layers with the index 0 and 1
By default, the Idem property is empty, which indicates hat has no effect. You can use the Idem property to rotate or move multiple layers once user drags a layer. The Item property of the Layers collection accesses a Layer giving its index or key. The Key property retrieves or sets the layer's key. The Index property is read-only and zero-based, which indicates that the layer with the Index property 0, it is the first layer, while the layer with the index Count - 1, is the last layer in the control ( in z-order ).