Disable Button in System Form

Dear SAP experts,

I have a rather interesting problem disabling a button from a system form.

I am trying to disable the 'Copy To' button from marketing documents (ID = "10000329");

I disable it using the following instruction:

oForm.Items.Item("10000329").Enabled = false;

It seems to work and in fact the button is grayed out as expected.

However, when I resize the form, the button becomes enabled by itself, even though I didn't change it. The problem also appears when I set it to Visible = false, and also when I set those two properties at the same time.

Surprisingly enough, other buttons don't show this behavior, for example the 'Add' Button (ID = "1").

Does anyone know why? How can I prevent this to happen?

I also tried to change the position of the button outside the form using negative coordinates (so it won't be visible), but it is fairly difficult to locate it in the original coordinates to make it visible again because after resizing, the system refuses to put it back in its place.

Best regards and thanks in advance.

N