Fuintur:
I am not positive about your issue, but when placing Figures for reference I will do 2 things:
1. Check the Transparent option in the Figure dialog box.
2. Lock the Figure after getting it to the correct size and placement.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
HTH
David