Forbbiden Blocks in my blueprint

It seems that the markerblock is not in the creative menu, unless it's with the right mouse button in one of the objects which I don't know.

 

I am not entirely sure but try to use ONE RED Core and right click on it it should open a bunch or other stuff used for POI Builder.

 

I found the description how @jrandall removed all RCS from a built



Starting with 14:45

 

My problem was solved with this command:

replaceblocks 7195 MarkerBlock empty

where 7195 is my BP structure ID after spawning it in the game with the sbp command. The command above erases all markerblocks which are forbidden in BPs. Also my structure didn't contain plants or personal containers or alien objects, so this was the solution.
Time for me to add this to my game notes...

Thank you all!