Page with sidebar: can't choose width

[farconada]

Can't choose sidebar width, only values 1,10,11 makes the form validate
TYPO3 7.6.2
fluidbt/fluidbootstraptheme dev-development e184baf The fluid_bootstrap package from FluidTYPO3
fluidtypo3/fluidcontent dev-master 5cd232c Create Flexible Content elements in pure fluid
fluidtypo3/fluidcontent_core 1.4.0 Replace css_styled_content with your own templates
fluidtypo3/fluidpages dev-master 8528e2f The fluidpages package from FluidTYPO3
fluidtypo3/flux dev-master b3acbf1 The flux package from FluidTYPO3
fluidtypo3/vhs dev-master 59f7cd9 The vhs package from FluidTYPO3
typo3-ter/fluidcontent 4.4.0 Fluid Content Element engine - integrates extremely compact and highly dynamic content element templates written in Fluid. See: https://github.com/FluidTYPO3/fluidcontent
typo3-ter/fluidpages 3.4.0 Fluid Page Template engine - integrates compact and highly dynamic page templates with all the benefits of Fluid.
typo3-ter/flux 7.3.0 Backend form and frontend content rendering assistance API with focus on productivity.
typo3-ter/news 4.0.0 Versatile news extension, based on extbase & fluid. Editor friendly, default integration of social sharing and many other features