I try bind a data to property "value" of spinner control but any no data type works. Try pass double like the "Ruler tool tutorial"
https://community.coreldraw.com/sdk/w/articles/218/creating-ruler-tool-for-coreldraw-or-corel-designer
try use wrapper double, marshal types.
Any light
entire xslt code
https://github.com/bonus630/FacaCaixaAutoToolBar/blob/master/FacaCaixaAutoToolBar/AppUI.xslt
entrie datasource code
https://github.com/bonus630/FacaCaixaAutoToolBar/blob/master/FacaCaixaAutoToolBar/DataSource/FacaDataSource.cs