I broke the UI while I was trying to check for another bug

I broke the UI. I feel really bad about it, though.

Steps to reproduce:
I have no idea what I did. I was looking at building materials for the building thingy, and then BAM. Dead.

Expected Results:
I didn’t expect this to happen.

Actual Results:
This happened.


develop-2924 (x64)
Uncaught TypeError: Cannot read property ‘destroy’ of undefined
TypeError: Cannot read property ‘destroy’ of undefined
at Object. (http://radiant/stonehearth/ui/game/modes/build_mode/building_cost/building_cost.js:85:33)
at fire (http://radiant/stonehearth/ui/root/js/libs/jquery-1.10.2.js:3048:30)
at Object.self.add (http://radiant/stonehearth/ui/root/js/libs/jquery-1.10.2.js:3094:7)
at SimpleClass.extend.progress (http://radiant/stonehearth/ui/game/population/population.js:108:25)
at http://radiant/stonehearth/ui/game/modes/build_mode/building_cost/building_cost.js:73:20
at Object. (http://radiant/radiant/js/radiant/object.js:295:19)
at Function.jQuery.extend.each (http://radiant/stonehearth/ui/root/js/libs/jquery-1.10.2.js:665:23)
at Object.radiant.each (http://radiant/radiant/js/radiant/object.js:293:15)
at null._transformCost (http://radiant/stonehearth/ui/game/modes/build_mode/building_cost/building_cost.js:71:21)
at applyStr (http://radiant/stonehearth/ui/root/js/libs/ember-1.8.1.js:19689:29)

Picture and such.

Version Number and Mods in use:
develop-2924 (x64)

System Information:
Super Fancy.

Edit: It looks like this happened again. I was opening the carpenter’s window on top of a building that I was making to find out which objects I needed for the building, and BAM.