Build pane disappears after changing the version number

I have been developing a package that is being used internally within my company. Every time I update it, I build it into a tar.gz and distribute it. Recently, I added a significant functionality and updated the "Version:" property in the .Rproj file from 1.0 to 1.1 (I know I really need to following the major.minor.patch approach! I hope that's the problem here). Now when I open the package/project by opening the .Rproj file on RStudio, the build pane at the top right corner disappears! I revert the version number to 1.0 and the build pane appears! Does anyone know how to increment the version number when building packages?