Non-fatal error on opening the app

[matherealize]

Upon running the app from rstudio I get the following message in the R console:

Warning: Error in if: argument is of length zero
  96: renderUI [SAMBA1/server.R#106]
  95: func
  82: origRenderFunc
  81: output$formula.fp
   1: runApp

Steps to reproduce:

• Run the app from rstudio at revision 85277d53f004fcd0947ab6c712ab98c4b445dd10