Issue description:
I use a Space Chamber Card and I wanted to see where he move the blocks and then he start to work with out clicking on start.
Steps to reproduce:
Build a Space Chamber then take a Card and put it in the Builder and Click on Preview Mode
Versions:

• Minecraft: 1.12.2
• Forge: 14.23.2.2613
• McJtyLib: 2.6.7
• RFTools: 7.32

Possibly incompatible mods and versions: I'm playing the DNS Techpack at v12.0.7.1 with Optifine

Show a screenshot of the gui of the builder