Undoing or other converts Peg pen into brick pen.

By some ungodly reason, everytime i undo, anything, not even interacting with the line of pegs, it turns into a brick pen, what causes this is weird, but if needed i'll supply with steps to reproduce.

[Moses2525]

Steps to reproduce:

1. Make any peg pen path.
2. Do anything that can be undone, examples: placing a peg or brick
3. Press undo.
   Presto! your peg pen path has become a brick pen path
   edit: I need to proof read dang it! had is now the word has