BaseLink pointer is changed after ctrl-z

[Helper]

On 11/02/2018 at 08:50, xxxxxxxx wrote:

User Information:
Cinema 4D Version:   R18 
Platform:   Windows  ;   
Language(s) :     C++  ;

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Hello.

I have a BaseLink pointing to a BaseMaterial.
If I change the material and then press ctrl-z, BaseLink shows to a different pointer. 
Is this behavior normal ?

Thank you for your time.

[Helper]

On 12/02/2018 at 05:30, xxxxxxxx wrote:

Hi,

yes, this is normal or expected behavior. Depending on the type of an created undo step, an entity may get copied onto the undo stack. Then later on, when the action is being undone, the copy gets moved back into the scene.