According the description of Ti.UI.View.borderWidth,
If borderColor is set without borderWidth, this value will be changed to 1 of the unit declared as 'ti.ui.defaultunit' in tiapp.xml descriptor.
Titanium Windows doesn't implement it, it remains 0 even after borderColor is set.
Expected: Red border should be shown around blue view.
Support for 'ti.ui.defaultunit' is split into