Designate A Zone For Slag Bug, Cannot Accomplish the Goal

Issue description

I've had a few restarts lately but this is the first time that I cannot accomplish this task. I've reloaded multiple times and tried various suggested methods to clear this goal of "Designate a dump zone for slag"

I have tried building a tower with slag already selectable as allowed, building a tower with nothing allowed until after built and just building the standard tower with the 4 pre-selected allowable elements. I have checked and unchecked the allowable materials on the trucks tab.

Reproduction steps

Attached game file and screen shots of the event, unable to accomplish task.

Game version and build number

v0.7.9 b495

Operating system

Windows

Attachments

![Image]

Dawgin'.save

(492531655-2370e6b8-9d10-432b-9201-1a16e341bbf7.jpg)

I have this issue currently. Just came back to the game, been restarting a few times and this is the first time I even register this step. Usually trigger this before it shows up. This time however it seems to be stuck. Got a dedicated control tower for slag as well.

Screenshot shows my slag dump and iron ore mine.

Version: Update 3 - v0.7.9a (b500)
Seed: qrarjebf6iit

Same here.