Replace text on a Master Page via Docker

Hi folks,

Perhaps this is just eluding me, but is there a way to find/replace text when it appears on a Master Page?

I have a template set-up on a Master Page where there is a series of numbers that appears on multiple places.  I have a placeholder like "000" on the template.

Before I started using the Master Page I could go to the Find and Replace docker, Find and Replace Text and it worked flawlessly.

Now that I've moved the text to the Master Page this no longer seems to work.  It's definitely not a show stopper, but it's inconvenient to say the least.

Any suggestions?