Recreate Window object and use it, by default it will not contain these parameter in PluginFurnitureCatalog.properties.

doorOrWindowSashXAxis#1=75 225
doorOrWindowSashYAxis#1=15 15
doorOrWindowSashWidth#1=75 75
doorOrWindowSashStartAngle#1=0 180
doorOrWindowSashEndAngle#1=90 90

--> Step
- Select Window object.
- Export to OBJ format (give new name)
- Import Furniture (new object)

You have new window without Circular arc.