Error Attribute "buttonSize" already defined error in xamarin forms

Hi friends,
My xamarin forms project am getting a strange issue if anyone got this issue before, please help he to resolve
Severity Code Description Project File Line Suppression State Error Attribute "buttonSize" already defined with incompatible format. eoTouchApp.Droid E:\office\working copy\fromUS\eoTouchApp\eoTouchApp.Droid\obj\Debug\resourcecache\5341E48E22B2B5D6FA5EDA719C18B9ED\res\values\base_attrs.xml12

"Attribute "buttonSize" already defined "
am using vis2015 for development ,

XamarinForms 2.3.3.193
XamarinFormsMap 2.3.3.193
xam.plugin.Geolocater 3.0.4
let me know any idea how to resolve this issue